Terminal device, base station apparatus, communication method, and integrated circuit

ABSTRACT

A user equipment includes a receiver configured to receive a PDSCH and a transmitter configured to transmit a HARQ-ACK response for a serving cell. In a first case that the user equipment communicates with at least a serving cell having a duplex mode that is TDD, the transmitter is configured to transmit, in a primary cell, the HARQ-ACK response in an uplink subframe n upon detection of a PDSCH transmission in the serving cell within a subframe n−k. In a second case that the user equipment communicates with a primary cell and a secondary cell, duplex mode of the primary cell being FDD, the transmitter is configured to transmit, in the primary cell, the HARQ-ACK response in an uplink subframe m upon detection of a PDSCH transmission in the secondary cell in only a subframe m−4.

TECHNICAL FIELD

The present invention relates to a terminal device, a base stationapparatus, a communication method, and an integrated circuit.

This application is based upon and claims the benefit of priority of theprior Japanese Patent Application No. 2013-232034, filed on Nov. 8,2013, the entire contents of which are incorporated herein by reference.

BACKGROUND ART

A base station apparatus (a base station, a cell, a first communicationapparatus (communication apparatus different from a terminal device),and eNodeB), and a terminal device (a terminal, a mobile terminal, amobile station apparatus, a second communication apparatus(communication apparatus different from the base station apparatus),user equipment (UE), and a user device) are included in a communicationsystem such as Wideband Code Division Multiple Access (WCDMA)(registered trademark), Long Term Evolution (LTE), and LTE-Advanced(LTE-A) by Third Generation Partnership Project (3GPP), and a WirelessLocal Area Network (WLAN), and Worldwide Interoperability for MicrowaveAccess (WiMAX) by The Institute of Electrical and Electronics engineers(IEEE). Each of the base station apparatus and the terminal deviceincludes a plurality of transmit/receive antennae. The base stationapparatus and the terminal device perform spatial multiplexing on a datasignal by using a Multi Input Multi Output (MIMO) technology, and thushigh-speed data communication is realized.

In 3GPP, in order to realize high-speed data communication between thebase station apparatus and the terminal device, carrier aggregation (CA)in which simultaneous communication is performed by using a plurality ofcomponent carriers is employed (NPL 1).

In 3GPP, as a frame structure type of a bi-directional communicationscheme (duplex communication scheme), frequency division duplex (FDD)and time division duplex (TDD) are employed. In FDD, a full duplexscheme in which bi-directional communication can be simultaneouslyperformed, and a half duplex scheme in which uni-directionalcommunication is switched and thus the bi-directional communication isrealized are employed (NPL 2). There is also a case where LTE employingthe TDD is referred to as TD-LTE or LTE TDD.

In 3GPP, TDD-FDD carrier aggregation (TDD-FDD CA) in which a componentcarrier (TDD carrier) which supports the TDD, and a component carrier(FDD carrier) which supports the FDD are aggregated and communication isperformed is examined (NPL 3).

CITATION LIST Non Patent Document

[Non Patent Document 1]

-   3rd Generation Partnership Project Technical Specification Group    Radio Access Network; Evolved Universal Terrestrial Radio Access    (E-UTRA) and Evolved Universal Terrestrial Radio Access Network    (E-UTRAN); Overall description; Stage 2 (Release 10), TS36.300    v10.10.0 (2013 June).    [Non Patent Document 2]-   3rd Generation Partnership Project Technical Specification Group    Radio Access Network; Evolved Universal Terrestrial Radio Access    (E-UTRA); Physical Channels and Modulation (Release 8), TS36.211    v8.8.0 (2009 September).    [Non Patent Document 3]-   “Potential solutions of TDD-FDD joint operation”, R1-132886, 3GPP    TSG-RAN WG1 Meeting #74, Barcelona, Spain, 19-23 Aug. 2013.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention

In carrier aggregation performed by a TDD cell and an FDD cell, amechanism in which HARQ response information which corresponds to aPDCCH/EPDCCH indicating a cell PDSCH of a certain frame constitutiontype, or a PDCCH/EPDCCH indicating SPS release is transmitted andreceived to and from a cell of a frame constitution type which isdifferent from the above cells is not provided. Thus, there is a problemin that appropriate communication is not performed.

Considering the above problem, an object of an aspect of the presentinvention is to provide a terminal and a base station which allowappropriate communication.

Means for Solving the Problems

(1) According to an aspect of the present invention, there is provided aterminal device which includes a transmission unit that transmits hybridautomatic retransmit request response information. In a case where oneserving cell is configured in the terminal device in time divisionduplex, or in a case where serving cells of which the number is morethan one are configured in the terminal device and uplink/downlinkconfigurations of all of the configured serving cells are the same aseach other, the transmission unit transmits the hybrid automaticretransmit request response information in an uplink subframe n, inresponse to detection of physical downlink control channel transmissionin a subframe (n−k). The transmission unit transmits the hybridautomatic retransmit request response information in an uplink subframem, in response to detection of physical downlink control channeltransmission in a subframe (m−4), in a primary cell having Frameconstitution type 1, in which frequency division duplex-time divisionduplex carrier aggregation is performed. The k is a component of adownlink association set K.

(2) In the terminal device according to (1), in the physical downlinkcontrol channel transmission, the terminal device may be set as atarget, and the hybrid automatic retransmit request response informationmay be provided for the physical downlink control channel transmission.

(3) In the terminal device according to (1), in a case where servingcells of which the number is more than one are configured in theterminal device, and two serving cells among the configured servingcells have frame constitution types different from each other, thefrequency division duplex-time division duplex carrier aggregation maybe configured in the terminal device.

(4) In the terminal device according to (1), the downlink associationset K may be determined based on the uplink subframe n and a timedivision duplex uplink/downlink configuration.

(5) In the terminal device according to (1), the Frame constitution type1 may be allowed to be applied to the frequency division duplex.

(6) According to another aspect of the present invention, there isprovided a terminal device which includes a transmission unit thattransmits hybrid automatic retransmit request response information. Infrequency division duplex, the transmission unit transmits the hybridautomatic retransmit request response information in a subframe n, inresponse to detection of physical downlink control channel transmissionin a subframe (n−4). In a case where a serving cell has Frameconstitution type 1, the transmission unit transmits the hybridautomatic retransmit request response information in a subframe m, inresponse to detection of physical downlink control channel transmissionin a subframe (m−k) for the serving cell, in a primary cell having Frameconstitution type 2, in which frequency division duplex-time divisionduplex carrier aggregation is performed. The k is a component of adownlink association set K.

(7) In the terminal device according to (6), in the physical downlinkcontrol channel transmission, the terminal device may be set as atarget, and the hybrid automatic retransmit request response informationmay be provided for the physical downlink control channel transmission.

(8) In the terminal device according to (6), in a case where servingcells of which the number is more than one are configured in theterminal device, and two serving cells among the configured servingcells have frame constitution types different from each other, thefrequency division duplex-time division duplex carrier aggregation maybe configured in the terminal device.

(9) In the terminal device according to (6), the downlink associationset K may be determined based on the subframe m and a time divisionduplex uplink/downlink configuration.

(10) In the terminal device according to (6), a secondary cell may notbe configured in the frequency division duplex.

(11) In the terminal device according to (6), the Frame constitutiontype 1 may be allowed to be applied to the frequency division duplex.

(12) In the terminal device according to (6), the Frame constitutiontype 2 may be allowed to be applied to time division duplex.

(13) In the terminal device according to (12), the serving cell may beconfigured as a secondary cell in the primary cell having the Frameconstitution type 2, in which the frequency division duplex-timedivision duplex carrier aggregation is performed.

(14) In the terminal device according to (13), in a case where theserving cell is the secondary cell having the Frame constitution type 1,a downlink reference uplink/downlink configuration for the serving cellmay be an uplink/downlink configuration for the primary cell, in theprimary cell having the Frame constitution type 2, in which thefrequency division duplex-time division duplex carrier aggregation isperformed, and the Frame constitution type 1 may be allowed to beapplied to the frequency division duplex.

(15) In the terminal device according to (14), in a case where theserving cell has the Frame constitution type 1, and the downlinkreference uplink/downlink configuration for at least one serving cell isa time division duplex uplink/downlink configuration 5, in the primarycell having the Frame constitution type 2, in which the frequencydivision duplex-time division duplex carrier aggregation is performed,serving cells of which the number is more than two may not be configuredin the terminal device.

(16) According to still another aspect of the present invention, thereis provided a base station apparatus which communicates with a terminaldevice. The base station apparatus includes a reception unit thatreceives hybrid automatic retransmit request response information. In acase where one serving cell is configured in the terminal device in timedivision duplex, or in a case where serving cells of which the number ismore than one are configured in the terminal device, and uplink/downlinkconfigurations of all of the configured serving cells are the same aseach other, the reception unit receives the hybrid automatic retransmitrequest response information in an uplink subframe n, in response tophysical downlink control channel transmission in a subframe (n−k). Thereception unit receives the hybrid automatic retransmit request responseinformation in an uplink subframe m, in response to physical downlinkcontrol channel transmission in a subframe (m−4), in a primary cellhaving Frame constitution type 1, in which frequency divisionduplex-time division duplex carrier aggregation is performed. The k is acomponent of a downlink association set K.

(17) In the base station apparatus according to (16), in the physicaldownlink control channel transmission, the terminal device may be set asa target, and the hybrid automatic retransmit request responseinformation may be provided for the physical downlink control channeltransmission.

(18) In the base station apparatus according to (16), in a case whereserving cells of which the number is more than one are configured in theterminal device, and two serving cells among the configured servingcells have frame constitution types different from each other, thefrequency division duplex-time division duplex carrier aggregation maybe configured in the terminal device.

(19) In the base station apparatus according to (16), the downlinkassociation set K may be determined based on the uplink subframe n and atime division duplex uplink/downlink configuration.

(20) In the base station apparatus according to (16), the Frameconstitution type 1 may be allowed to be applied to the frequencydivision duplex.

(21) According to still another aspect of the present invention, thereis provided a base station apparatus which communicates with a terminaldevice. The base station apparatus includes a reception unit thatreceives hybrid automatic retransmit request response information. Infrequency division duplex, the reception unit receives the hybridautomatic retransmit request response information in a subframe n, inresponse to physical downlink control channel transmission in a subframe(n−4). In a case where a serving cell has Frame constitution type 1, thereception unit receives the hybrid automatic retransmit request responseinformation in a subframe m, in response to physical downlink controlchannel transmission in a subframe (m−k) for the serving cell, in aprimary cell having Frame constitution type 2, in which frequencydivision duplex-time division duplex carrier aggregation is performed.The k is a component of a downlink association set K.

(22) In the base station apparatus according to (21), in the physicaldownlink control channel transmission, the terminal device may be set asa target, and the hybrid automatic retransmit request responseinformation may be provided for the physical downlink control channeltransmission.

(23) In the base station apparatus according to (21), in a case whereserving cells of which the number is more than one are configured in theterminal device, and two serving cells among the configured servingcells have frame constitution types different from each other, thefrequency division duplex-time division duplex carrier aggregation maybe configured in the terminal device.

(24) In the base station apparatus according to (21), the downlinkassociation set K may be determined based on the subframe m and a timedivision duplex uplink/downlink configuration.

(25) In the base station apparatus according to (21), a secondary cellmay not be configured in the frequency division duplex.

(26) In the base station apparatus according to (21), the Frameconstitution type 1 may be allowed to be applied to the frequencydivision duplex.

(27) In the base station apparatus according to (21), the Frameconstitution type 2 may be allowed to be applied to time divisionduplex.

(28) In the base station apparatus according to (27), the serving cellmay be configured as a secondary cell in the primary cell having theFrame constitution type 2, in which the frequency division duplex-timedivision duplex carrier aggregation is performed.

(29) In the base station apparatus according to (28), in a case wherethe serving cell is the secondary cell having the Frame constitutiontype 1, an uplink/downlink configuration for the primary cell may be adownlink reference uplink/downlink configuration for the serving cell,in the primary cell having the Frame constitution type 2, in which thefrequency division duplex-time division duplex carrier aggregation isperformed. The Frame constitution type 1 may be allowed to be applied tothe frequency division duplex.

(30) In the base station apparatus according to (29), in a case wherethe serving cell has the Frame constitution type 1, and the downlinkreference uplink/downlink configuration for at least one serving cell isa time division duplex uplink/downlink configuration 5, in the primarycell having the Frame constitution type 2, in which the frequencydivision duplex-time division duplex carrier aggregation is performed,serving cells of which the number is more than two may not be configuredin the terminal device.

(31) According to still another aspect of the present invention, thereis provided a communication method of a terminal device. The methodincludes a step of transmitting hybrid automatic retransmit requestresponse information in an uplink subframe n, in response to detectionof physical downlink control channel transmission in a subframe (n−k),in a case where one serving cell is configured in the terminal device intime division duplex, or in a case where serving cells of which thenumber is more than one are configured in the terminal device anduplink/downlink configurations of all of the configured serving cellsare the same as each other, and a step of transmitting the hybridautomatic retransmit request response information in an uplink subframem, in response to detection of physical downlink control channeltransmission in a subframe (m−4), in a primary cell having Frameconstitution type 1, in which frequency division duplex-time divisionduplex carrier aggregation is performed. The k is a component of adownlink association set K.

(32) According to still another aspect of the present invention, thereis provided a communication method of a terminal device. The methodincludes a step of transmitting hybrid automatic retransmit requestresponse information in a subframe n, in response to detection ofphysical downlink control channel transmission in a subframe (n−4), infrequency division duplex, a step of transmitting the hybrid automaticretransmit request response information in a subframe m, in response todetection of physical downlink control channel transmission in asubframe (m−k) for a serving cell, in a primary cell having Frameconstitution type 2, in which frequency division duplex-time divisionduplex carrier aggregation is performed, in a case where the servingcell has Frame constitution type 1. The k is a component of a downlinkassociation set K.

(33) According to still another aspect of the present invention, thereis provided a communication method of a base station apparatus whichcommunicates with a terminal device. The method includes a step ofreceiving hybrid automatic retransmit request response information in anuplink subframe n, in response to physical downlink control channeltransmission in a subframe (n−k), in a case where one serving cell isconfigured in the terminal device in time division duplex, or in a casewhere serving cells of which the number is more than one are configuredin the terminal device, and uplink/downlink configurations of all of theconfigured serving cells are the same as each other, and a step ofreceiving the hybrid automatic retransmit request response informationin an uplink subframe m, in response to physical downlink controlchannel transmission in a subframe (m−4), in a primary cell having Frameconstitution type 1, in which frequency division duplex-time divisionduplex carrier aggregation is performed. The k is a component of adownlink association set K.

(34) According to still another aspect of the present invention, thereis provided a communication method of a base station apparatus whichcommunicates with a terminal device. The method includes a step ofreceiving hybrid automatic retransmit request response information in asubframe n, in response to physical downlink control channeltransmission in a subframe (n−4), in frequency division duplex, and astep of receiving the hybrid automatic retransmit request responseinformation in a subframe m, in response to physical downlink controlchannel transmission in a subframe (m−k) for a serving cell, in a casewhere the serving cell has Frame constitution type 1 in a primary cellhaving Frame constitution type 2, in which frequency divisionduplex-time division duplex carrier aggregation is performed. The k is acomponent of a downlink association set K.

(35) According to still another aspect of the present invention, thereis provided an integrated circuit mounted in a terminal device. Thecircuit includes a function of transmitting hybrid automatic retransmitrequest response information in an uplink subframe n, in response todetection of physical downlink control channel transmission in asubframe (n−k), in a case where one serving cell is configured in theterminal device in time division duplex, or in a case where servingcells of which the number is more than one are configured in theterminal device and uplink/downlink configurations of all of theconfigured serving cells are the same as each other, and a function oftransmitting the hybrid automatic retransmit request responseinformation in an uplink subframe m, in response to detection ofphysical downlink control channel transmission in a subframe (m−4), in aprimary cell having Frame constitution type 1, in which frequencydivision duplex-time division duplex carrier aggregation is performed.The k is a component of a downlink association set K.

(36) According to still another aspect of the present invention, thereis provided an integrated circuit mounted in a terminal device. Thecircuit includes a function of transmitting hybrid automatic retransmitrequest response information in a subframe n, in response to detectionof physical downlink control channel transmission in a subframe (n−4),in frequency division duplex, and a function of transmitting the hybridautomatic retransmit request response information in a subframe m, inresponse to detection of physical downlink control channel transmissionin a subframe (m−k) for a serving cell, in a primary cell having Frameconstitution type 2, in which frequency division duplex-time divisionduplex carrier aggregation is performed, in a case where the servingcell has Frame constitution type 1. The k is a component of a downlinkassociation set K.

(37) According to still another aspect of the present invention, thereis provided an integrated circuit mounted in a base station apparatuswhich communicates with a terminal device. The circuit includes afunction of receiving hybrid automatic retransmit request responseinformation in an uplink subframe n, in response to physical downlinkcontrol channel transmission in a subframe (n−k), in a case where oneserving cell is configured in the terminal device in time divisionduplex, or in a case where serving cells of which the number is morethan one are configured in the terminal device, and uplink/downlinkconfigurations of all of the configured serving cells are the same aseach other, and a function of receiving the hybrid automatic retransmitrequest response information in an uplink subframe m, in response tophysical downlink control channel transmission in a subframe (m−4), in aprimary cell having Frame constitution type 1, in which frequencydivision duplex-time division duplex carrier aggregation is performed.The k is a component of a downlink association set K.

(38) According to still another aspect of the present invention, thereis provided an integrated circuit mounted in a base station apparatuswhich communicates with a terminal device. The circuit includes afunction of receiving hybrid automatic retransmit request responseinformation in a subframe n, in response to physical downlink controlchannel transmission in a subframe (n−4), in frequency division duplex,and a function of receiving the hybrid automatic retransmit requestresponse information in a subframe m, in response to physical downlinkcontrol channel transmission in a subframe (m−k) for a serving cell, ina case where the serving cell has Frame constitution type 1 in a primarycell having Frame constitution type 2, in which frequency divisionduplex-time division duplex carrier aggregation is performed. The k is acomponent of a downlink association set K.

Effects of the Invention

According to any aspect of the invention, in a communication system inwhich the base station apparatus and the terminal device communicatewith each other, the terminal device performs appropriate transmissioncontrol and reception control, and thus it is possible to improvecommunication efficiency.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic block diagram illustrating a configuration of abase station apparatus 1 according to a first embodiment of the presentinvention.

FIG. 2 is a schematic block diagram illustrating a configuration of aterminal device 2 according to the first embodiment of the presentinvention.

FIG. 3 is a diagram illustrating a configuration of a subframe patternin a TDD UL/DL configuration.

FIG. 4 is a diagram illustrating an example of mapping of a PUCCHresource for HARQ response information, which corresponds to a PDCCHaccording to the first embodiment of the present invention.

FIG. 5 is a diagram illustrating an example of mapping of a PUCCHresource for the HARQ response information, which corresponds to anEPDCCH according to the first embodiment of the present invention.

FIG. 6 is a diagram illustrating a correspondence between a subframe inwhich a PDCCH/EPDCCH is transmitted, and a subframe in which the HARQresponse information is transmitted, according to the first embodimentof the present invention.

FIG. 7 is a diagram illustrating a calculation expression of PUCCHresources including the HARQ response information in TDD according tothe first embodiment of the present invention.

FIG. 8 is a diagram illustrating an example of a transmission timing ofthe HARQ response information in carrier aggregation between TDD andFDD, according to the first embodiment of the present invention.

FIG. 9 is a diagram illustrating an example of a correspondence betweena subframe in which the PDCCH/EPDCCH is transmitted and a subframe inwhich the HARQ response information is transmitted, in the carrieraggregation between TDD and FDD according to the first embodiment of thepresent invention.

FIG. 10 is a diagram illustrating a correspondence between a combinationof UL-DL configurations and a downlink reference UL-DL configuration,according to the first embodiment of the present invention.

MODE FOR CARRYING OUT THE INVENTION

In a communication system of an embodiment, carrier aggregation in whicha plurality of component carriers are aggregated (summed, collected) soas to perform communication is applied. Because a cell may be configuredby using a component carrier, the carrier aggregation may be referred toas cell aggregation. That is, the communication system according to theembodiment may perform communication by using integration of a pluralityof cells. In the communication system according to the embodiment, thecell aggregation aggregates a cell (TDD cell, TDD serving cell, TDDcarrier, and TDD component carrier) to which a TDD scheme is applied,and a cell (FDD cell, FDD serving cell, FDD carrier, and FDD componentcarrier) to which an FDD scheme is applied, among the plurality ofcells, and performs communication. That is, in the communication systemaccording to the embodiment, the cell aggregation is applied in aplurality of cells in which a different frame structure type isconfigured. The frame structure type may be referred to as duplex mode.In LTE and LTE-A, Frame structure type 1 is defined as the FDD, andFrame constitution type 2 is defined as the TDD.

In the cell aggregation, one primary cell and one or more secondarycells are aggregated so as to perform communication. The primary cellmay be configured by using an uplink component carrier and a downlinkcomponent carrier. On the contrary, the secondary cell may be configuredby using only a downlink component carrier.

A plurality of configured serving cells (plurality of configured cells)includes one primary cell and one or a plurality of secondary cells. Theprimary cell is a serving cell in which initial connection establishmentprocedure is performed, a serving cell in which connectionreestablishment procedure is started, or a cell instructed as a primarycell in a handover procedure. The secondary cell may be configured at apoint of time when or after RRC connection is established. A pluralityof serving cells may be constituted by one base station apparatus 1, anda plurality of serving cells may be constituted by a plurality of basestation apparatuses 1.

A frequency band in an uplink and a downlink (UL/DL operating band) anda duplex mode (TDD, FDD) are correlated with one index. The frequencyband in an uplink and a downlink (UL/DL operating band) and the duplexmode are managed on one table. This index may be also referred to as anE-UTRA operating band, an E-UTRA band, or a band. For example, Index 1may be also referred to as Band 1, Index 2 may be also referred to asBand 2, and Index n may be also referred to as Band n. For example, inBand 1, an uplink operating band is from 1920 MHz to 1980 MHz, adownlink operating band is from 2110 MHz to 2170 MHz, and the duplexmode is FDD. In Band 33, the uplink and downlink operating band is from1900 MHz to 1920 MHz, and the duplex mode is TDD.

A combination (E-UTRA CA Band) of bands in which performing carrieraggregation is possible may be configured. For example, the carrieraggregation performed by using component carriers in Band 1 and Band 5may be indicated to be possible. That is, it may be indicated whether ornot the carrier aggregation is performed by using component carriers inbands different from each other.

A combination of a band supported by a terminal device 2, and a band inwhich performing the carrier aggregation is possible is configured infunction information (UE capability, UE-EUTRA-Capability) of theterminal device 2. The base station apparatus 1 can recognize a functionincluded in the terminal device 2 by the terminal device 2 transmittingthe function information.

The present invention may be applied to some of a plurality ofconfigured cells. A cell configured in the terminal device 2 may be alsoreferred to as a serving cell.

TDD is a technology in which time division multiplexing is performed onan uplink signal and a downlink signal, and thus communication betweenan uplink and a downlink is allowed in a single frequency band (carrierfrequency, component carrier). In LTE, configuration is performed inadvance, and thus a downlink and an uplink may be switched in a subframeunit. In TDD, a subframe (downlink subframe, and subframe reserved fordownlink transmission) in which downlink transmission is allowed, and asubframe (uplink subframe, and subframe reserved for uplinktransmission) in which uplink transmission is allowed, and further aguard period (GP) are configured, and thus a subframe (special subframe)in which downlink transmission and uplink transmission can be switchedin a time region (symbol region) is defined. In a special subframe, atime region (symbol corresponding to the time region) in which downlinktransmission is allowed is referred to as a downlink pilot time slot(DwPTS), and a time region (symbol corresponding to the time region) inwhich uplink transmission is allowed is referred to as an uplink pilottime slot (UpPTS). For example, in a case where a subframe i is adownlink subframe in the terminal device 2, a downlink signaltransmitted from the base station apparatus 1 can be received. In a casewhere a subframe j different from the subframe i is an uplink subframe,an uplink signal can be transmitted from the terminal device 2 to thebase station apparatus 1. In a case where a subframe k which isdifferent from the subframe i or the subframe j is a special subframe, adownlink signal can be received in a downlink time region DwPTS, and anuplink signal can be transmitted in an uplink time region UpPTS.

In order to perform communication by using the TDD scheme in LTE andLTE-A, notification is performed by using a specific information element(TDD UL/DL (UL-DL) configuration (TDD UL/DL configuration(s), TDDuplink-downlink configuration(s)), TDD configuration (TDDconfiguration(s), tdd-Config, TDD config), and UL/DL (UL-DL)configuration (uplink-downlink configuration(s))). The terminal device 2may consider a certain subframe as any one of an uplink subframe, adownlink subframe, and a special subframe, based on notifiedinformation, and may perform transmission and reception processing.

Regarding a constitution of a special subframe (DwPTS, UpPTS, and lengthof GP in the special subframe), a plurality of patterns is defined, andis managed in a manner of a table. The plurality of patterns iscorrelated with values (indices), and notification of the valuecorresponding to the pattern is performed, and thus the terminal deviceperforms processing of the special subframe. That is, notification ofinformation regarding constitution of the special subframe may beperformed from the base station apparatus 1 to the terminal device 2.

A traffic adaptive control technology in which a ratio of an uplinkresource and a downlink resource is changed in accordance with trafficof an uplink and traffic of a downlink (information quantity, dataquantity, and communication volume) may be applied to TDD. For example,a ratio of a downlink subframe and an uplink subframe may be dynamicallychanged. Regarding a certain subframe, the downlink subframe and theuplink subframe may be adaptively switched. Such a subframe is referredto as a flexible subframe. The base station apparatus 1 can receive anuplink signal or transmit a downlink signal in a flexible subframe, inaccordance with a condition (situation). The terminal device 2 mayperform reception processing considering a flexible subframe as thedownlink subframe, as long as the base station apparatus 1 does notperform an instruction of transmission of an uplink signal in theflexible subframe. Such TDD in which the ratio of the downlink subframeand the uplink subframe, subframes of the uplink and the downlink, orthe TDD UL/DL (re)configuration is dynamically changed may be alsoreferred to as dynamic TDD (DTDD) or enhanced interference mitigationand traffic adaptation (eIMTA). For example, TDD UL/DL configurationinformation may be transmitted through L1 signaling.

FDD is a technology in which communication between a downlink and anuplink is allowed different frequency bands (carrier frequencies,component carriers).

As the communication system, a cellular communication system in which aplurality of areas which are covered by the base station apparatus 1 andhave a cell shape is disposed may be applied. A single base stationapparatus 1 may manage a plurality of cells. A single base stationapparatus 1 may manage a plurality of remote radio heads (RRHs). Asingle base station apparatus 1 may manage a plurality of local areas. Asingle base station apparatus 1 may manage a plurality of heterogeneousnetworks (HetNets). A single base station apparatus 1 may manage aplurality of low power base station apparatuses (LPN: Low Power Node).

In the communication system, the terminal device 2 measures referencesignal received power (RSRP) based on a cell specific referencesignal(s) (CRS).

In the communication system, communication may be performed by usingcarriers (component carriers) in which some of physical channels orsignals defined in LTE are not mapped. Here, such a carrier is referredto as a new carrier type (NCT). For example, in the new carrier type, acell specific reference signal, a physical downlink control channel, ora synchronization signal (primary synchronization signal, secondarysynchronization signal) may be not mapped. In a cell in which the newcarrier type is configured, application of a physical channel (PDCH:Physical Discovery Channel, NDS: New Discovery Signal(s), DRS: DiscoveryReference Signal, and DS: Discovery Signal) for measuring mobility ordetecting time/frequency synchronization is examined. The new carriertype may be also referred to as an additional carrier type (ACT).Regarding the NCT, a known carrier type may be also referred to as alegacy carrier type (LCT).

In the embodiment, “X/Y” includes a meaning of “X or Y”. In theembodiment, “X/Y” includes a meaning of “X and Y”. In the embodiment,“X/Y” includes a meaning of “X and/or Y”.

(Physical Channel)

The main physical channel (or physical signal) used in LTE and LTE-Awill be described. The channel means a medium used in transmission of asignal. The physical channel means a physical medium used intransmission of a signal. The physical channel may be added after now,or the structure or a format type thereof may be changed or added in LTEand LTE-A, and release of the subsequent standard. However, even whensuch a case occurs, the case does not influence the descriptions for theembodiment of the present invention.

In LTE and LTE-A, scheduling of the physical channel is managed by usinga radio frame. One radio frame is 10 ms and one radio frame isconstituted by 10 subframes. Further, one subframe is constituted by 2slots (that is, one slot is 0.5 ms). The scheduling is managed by usinga resource block as a smallest unit for the scheduling, to which thephysical channel is allocated. The resource block is defined as a regionwhich includes a constant frequency region in which a frequency axis isconstituted by a set of a plurality of subcarriers (for example, 12subcarriers), and a constant transmission time interval (for example,one slot, seven symbols).

In order to improve communication accuracy, a cyclic prefix (CP)allocated to a redundant portion of the physical channel is applied tothe physical channel and is transmitted. The length of the CP causes thenumber of symbols allocated in one slot to be changed. For example, in acase of a normal CP, seven symbols may be allocated in one slot. In acase of an extended CP, six symbols may be allocated in one slot.

An interval between subcarriers is narrowed, and thus 24 subcarriers maybe allocated in one resource block. Such a case may be applied to aspecific physical channel.

The physical channel corresponds to a set of resource elements fortransmitting information which is output from a higher layer. A physicalsignal is used in a physical layer, and does not transmit informationwhich is output from a higher layer. That is, control information of ahigher layer, such as a radio resource control (RRC) message or systeminformation (SI) is transmitted on a physical channel.

As a downlink physical channel, there are a physical downlink sharedchannel (PDSCH), a physical broadcast channel (PBCH), a physicalmulticast channel (PMCH), a physical control format indicator channel(PCFICH), a physical downlink control channel (PDCCH), a physical hybridARQ indicator channel (PHICH), and an enhanced physical downlink controlchannel (EPDCCH). As a downlink physical signal, various referencesignals and various synchronization signals are provided. As a downlinkreference signal (DL-RS), there are a cell specific reference signal(CRS), an UE specific reference signal (UERS), and a channel stateinformation reference signal (CSI-RS). As a synchronization signal,there are a primary synchronization signal (PSS), and a secondarysynchronization signal (SSS).

As an uplink physical channel, there are a physical uplink sharedchannel (PUSCH), a physical uplink control channel (PUCCH), and aphysical random access channel (PRACH). As an uplink physical signal,various reference signals are provided. As an uplink reference signal,there are a demodulation reference signal (DMRS) and a soundingreference signal (SRS).

The synchronization signal is constituted by three types of PSSs, and anSSS. The SSS is constituted by 31 types of codes which are arranged atdifferent positions in a frequency domain. A physical layer cellidentity (PCI: physical layer cell identity, physical cell identity,physical cell identifier) and a frame timing for radio synchronizationare indicated by combining the PSS and the SSS. The physical layer cellidentity is used for identifying the base station apparatus 1 like 504.The terminal device 2 specifies a cell identifier of the receivedsynchronization signal, by cell searching. The cell identifier may bealso referred to as a cell ID. The physical layer cell identity may bealso referred to as a physical cell ID.

A physical broadcast channel (PBCH) is transmitted for the purpose ofperforming a notification of a control parameter (broadcast informationor system information) which is commonly used in terminal devices 2 in acell. Broadcast information (for example, SIB1 or portion of systeminformation) of which notification on the PBCH is not performed istransmitted through a DL-SCH on a PDSCH. Notification of a cell globalidentifier (CGI), a tracking area identifier (TAI), random accessconfiguration information (transmission timing timer and the like),common radio resource configuration information (shared radio resourceconfiguration information), and the like as the broadcast information isperformed. The cell global identifier (CGI) indicates an identifierspecific to a cell. The tracking area identifier is for managing an areawaiting by paging.

The downlink reference signal is classified into a plurality of types inaccordance with the use thereof. For example, the cell specificreference signal (CRS) is a pilot signal transmitted with predeterminedpower for each cell, and is a downlink reference signal of whichtransmission is periodically repeated in the frequency domain and in thetime domain, based on a predetermined rule. The terminal device 2receives the cell specific reference signal, and thus measures receptionquality for each cell. The terminal device 2 uses the cell specificreference signal as a reference signal for demodulating a physicaldownlink control channel or a physical downlink shared channeltransmitted by an antenna port which is the same as that used for thecell specific reference signal. As a sequence used for the cell specificreference signal, a sequence which can be identified for each cell isused. The CRS may be transmitted in all downlink subframes by the basestation apparatus 1. However, the terminal device 2 may receive the CRSonly on a designated downlink subframe.

The downlink reference signal is also used in estimating propagationfluctuation in a downlink. Each of downlink reference signals used inestimating propagation fluctuation may be referred to as a channel stateinformation reference signal (CSI-RS) or a CSI reference signal. A CSIreference signal which is not transmitted in practice or is transmittedwith zero power may be referred to as a zero power channel stateinformation reference signals (ZP CSI-RS) or a zero power CSI referencesignal. A CSI reference signal which is transmitted in practice may bereferred to as a non zero power channel state information referencesignal (NZP CSI-RS) or a non zero power CSI reference signal.

Each of downlink resources used in measuring an interference componentmay be referred to as a channel state information-interferencemeasurement resource (CSI-IMR) or a CSI-IM resource. The terminal device2 may measure interference signal by using a zero power CSI referencesignal included in a CSI-IM resource, so as to calculate a value of aCQI. A downlink reference signal which is configured dedicatedly foreach terminal device 2 is referred to as an UE specific reference signal(UERS) or a dedicated reference signal, a downlink demodulationreference signal (DL DMRS), and the like. Such a downlink referencesignal is used in demodulating the physical downlink control channel orthe physical downlink shared channel.

A sequence for the downlink reference signals may be generated based ona pseudo-random sequence. The sequence for the downlink referencesignals may be generated based on a Zadoff-Chu sequence. The sequencefor the downlink reference signals may be generated based on a Goldsequence. The sequence for the downlink reference signals may begenerated based on subspecies or modifications of the pseudo-randomsequence, the Zadoff-Chu sequence, or the Gold sequence.

The physical downlink shared channel (PDSCH) is used for transmittingdownlink data (DL-SCH). The PDSCH is also used in a case where systeminformation is transmitted on the DL-SCH. Radio resource assignmentinformation for the physical downlink shared channel is indicated by thephysical downlink control channel. The PDSCH is also used in performingnotification of a parameter (information element, RRC message) relatingto a downlink and an uplink.

The physical downlink control channel (PDCCH) is transmitted by usingsome OFDM symbols from the leading of each subframe, and is used forinstructing the terminal device 2 of resource assignment information oran adjusted quantity of an increase or a decrease of transmitted powerin accordance with scheduling of the base station apparatus 1. It isnecessary that the terminal device 2 monitors a physical downlinkcontrol channel thereof before a message of Layer 3 (paging, handovercommand, RRC message, and the like) is transmitted and received, andacquires resource assignment information from the physical downlinkcontrol channel. The resource assignment information is referred to asan uplink grant when transmission is performed, and is referred to as adownlink grant (also referred to as downlink assignment) when receptionis performed. The physical downlink control channel may be constitutedso as to be transmitted with the above-described OFDM symbols, and to betransmitted in a region of resource blocks which are dedicatedlyallocated to the terminal device 2 from the base station apparatus 1.The physical downlink control channel transmitted in the region of theresource blocks which are dedicatedly allocated to the terminal device 2from the base station apparatus 1 may be also referred to as an enhancedphysical downlink control channel (EPDCCH: Enhanced PDCCH). The PDCCHtransmitted with the above-described OFDM symbols may be also referredto as a first control channel. The EPDCCH may be also referred to as asecond control channel. The resource region to which the PDCCH can beallocated may be also referred to as a first control channel region. Theresource region to which the EPDCCH can be allocated may be alsoreferred to as a second control channel region. A PDCCH which will bedescribed later is assumed to basically include an EPDCCH.

The base station apparatus 1 may transmit a PCFICH, a PHICH, a PDCCH, anEPDCCH, a PDSCH, a synchronization signal (PSS/SSS), and a downlinkreference signal in a DwPTS of a special subframe. The base stationapparatus 1 may not transmit a PBCH in the DwPTS of the specialsubframe.

The terminal device 2 may transmit a PRACH and a SRS in an UpPTS of thespecial subframe. The terminal device 2 may not transmit a PUCCH, aPUSCH, and a DMRS in the UpPTS of the special subframe.

In a case where the special subframe is constituted only by a GP and anUpPTS, the terminal device 2 may transmit the PUCCH and/or the PUSCHand/or the DMRS in the UpPTS of the special subframe.

Here, the terminal device 2 monitors PDCCH candidates and/or EPDCCHcandidates. Hereinafter, for simple descriptions, a PDCCH may include anEPDCCH. The PDCCH candidates indicate candidates having a probability ofthe base station apparatus 1 mapping and transmitting a PDCCH. Each ofthe PDCCH candidates is constituted from one or a plurality of controlchannel elements (CCEs). The monitoring may include a case where theterminal device 2 attempts to decode each of PDCCHs in a set of thePDCCH candidates, in accordance to all monitored DCI formats.

Here, the set of PDCCH candidates monitored by the terminal device 2 isalso referred to as a search space. The search space means a set ofresources having a probability of being used in transmitting the PDCCHby the base station apparatus 1. A common search space (CSS) and aterminal device specific search space (USS: UE-specific search space)are constituted (defined, configured) in a PDCCH region.

The CSS is used in transmitting downlink control information to aplurality of terminal devices 2. That is, the CSS is defined by a commonresource for the plurality of terminal devices 2. The USS is used intransmitting the downlink control information to a certain specificterminal device 2. That is, the USS is dedicatedly configured for thecertain specific terminal device 2. The USS may be configured so as tobe duplicated in a plurality of terminal devices 2.

Downlink control information (DCI) is transmitted to the terminal device2 from the base station apparatus 1 in a specific format (constitution,form). The format may be referred to as a DCI format. Transmission ofthe DCI format includes a case where DCI having a certain format istransmitted. The DCI format may be restated as a format for transmittingthe DCI. As the DCI format transmitted to the terminal device 2 from thebase station apparatus 1, a plurality of formats is prepared (forexample, DCI format 0/1/1A/1B/1C/1D/2/2A/2B/2C/2D/3/3A/4). Fields (bitfields) corresponding to various types of downlink control informationare set in the DCI format.

In a case where common DCI (single DCI) is transmitted to a plurality ofterminal devices 2 in a certain DCI format, the base station apparatus 1performs transmission in a PDCCH (or EPDCCH) CSS. In a case where DCI isdedicatedly transmitted to each of the terminal devices 2 in a certainDCI format, the base station apparatus 1 performs transmission in aPDCCH (or EPDCCH) USS.

As the DCI transmitted in the DCI format, there are resource assignmentof a PUSCH or a PDSCH, modulation and coding scheme, a soundingreference signal request (SRS request), a channel state informationrequest (CSI request), an instruction of first transmission orretransmission of a single transport block, a transmitted power controlcommand for a PUSCH, a transmitted power control command for a PUCCH,cyclic shift of an UL DMRS, an index of an orthogonal code cover (OCC),and the like. In addition, various types of DCI are defined by aspecification document.

A format used in uplink transmission control (for example, scheduling ofa PUSCH, and the like) may be referred to as an uplink DCI format (forexample, DCI format 0/4) or DCI associated with an uplink. The uplinktransmission control may be referred to as an uplink grant. A formatused in downlink reception control (for example, scheduling of a PDSCH,and the like) may be referred to as a downlink DCI format (for example,DCI format 1/1A/1B/1C/1D/2/2A/2B/2C/2D), or DCI associated with adownlink. The downlink reception control may be referred to as adownlink grant, downlink assignment, or downlink allocation. A formatused for adjusting transmitted power of each of a plurality of terminaldevices 2 may be referred to as a group triggering DCI format (forexample, DCI format 3/3A).

For example, DCI format 0 is used for transmitting information regardingresource assignment of a PUSCH, which is required for performingscheduling of one PUSCH in one serving cell, or information regarding amodulation scheme, information regarding a transmitted power control(TPC) command for the PUSCH, and the like. The DCI is transmitted on aPDCCH/EPDCCH. It is stated that the DCI format is constituted by atleast one piece of DCI.

The terminal device 2 monitors PDCCHs in a CSS and/or a USS of a PDCCHregion, and detects a PDCCH of the terminal device 2.

An RNTI allocated to the terminal device 2 by the base station apparatus1 is used in transmitting downlink control information (transmission onthe PDCCH). Specifically, a cyclic redundancy check (CRC) parity bit isadded to a DCI format (which may be downlink control information), andafter addition is performed, the CRC parity bit is scrambled by usingthe RNTI.

The terminal device 2 attempts to decode a DCI format to which the CRCparity bit scrambled by using the RNTI is added, and detects a DCIformat of which the CRC is determined to succeed, as the DCI format ofthe terminal device 2 (such a process is also referred to blinddecoding). That is, the terminal device 2 attempts to decode a PDCCH inaccordance with the CRC scrambled by using the RNTI, and detects a PDCCHof which the CRC is determined to succeed, as the PDCCH of the terminaldevice 2.

Here, the RNTI includes a cell-radio network temporary identifier(C-RNTI). The C-RNTI is a unique identifier used for RRC connection andidentification of scheduling. The C-RNTI is used for uni-casttransmission which is dynamically scheduled.

The RNTI includes a Temporary C-RNTI. The Temporary C-RNTI is anidentifier used for a random access procedure. For example, the terminaldevice 2 may decode the DCI format (for example, DCI format 0) to whichthe CRC scrambled by using the Temporary C-RNTI is added and which isassociated with an uplink, only in the CSS. The terminal device 2 mayattempt to decode the DCI format (for example, DCI format 1A) to whichthe CRC scrambled by using the Temporary C-RNTI is added and which isassociated with a downlink, in the CSS and the USS.

In a case where the DCI is transmitted in the CSS, the base stationapparatus 1 adds a CRC parity bit scrambled by using the TemporaryC-RNTI or the C-RNTI, to the DCI (DCI format). In a case where the DCIis transmitted in the USS, the base station apparatus 1 may add CRCscrambled by using the C-RNTI, to the DCI (DCI format).

A physical uplink shared channel (PUSCH) is mainly used for transmittinguplink data and uplink control information (UCI). The UCI transmitted ona PUSCH includes channel state information (CSI), and/or ACK/NACK. TheCSI transmitted on a PUSCH includes aperiodic CSI (A-CSI) and periodicCSI (P-CSI). Similarly to a case of the downlink, resource assignmentinformation of the physical uplink shared channel is indicated by aphysical downlink control channel. The PUSCH scheduled by a dynamicscheduling grant transmits the uplink data. The PUSCH scheduled by arandom access response grant transmits information (for example,identification information of the terminal device 2, and Message 3) ofthe base station apparatus 1, which is associated to random access.Parameters used for setting transmitted power for transmission on thePUSCH may be different in accordance with the type of the detectedgrant. Control data is transmitted in a form of channel qualityinformation (CQI and/or PMI), HARQ response information (HARQ-ACK,HARQ-ACK response), and RI. That is, the control data is transmitted ina form of uplink control information.

A physical uplink control channel (PUCCH) is used for notification ofreception acknowledgement response (ACK/NACK: Acknowledgement/NegativeAcknowledgement) of downlink data transmitted on a physical downlinkshared channel, or notification of channel information (channel stateinformation) of a downlink, and is used for performing a schedulingrequest (SR) which is a resource assignment request (radio resourcerequest) of an uplink. Channel state information (CSI) includes achannel quality indicator (CQI), a precoding matrix indicator (PMI), aprecoding type indicator (PTI), and a rank indicator (RI). Each of theindicators may be described as indication, but the use and the meaningthereof is the same. A format of the PUCCH may be switched in accordancewith the transmitted UCI. For example, in a case where the UCI isconstituted from HARQ response information and/or SR, the UCI may betransmitted on a PUCCH of a format 1/1a/1b/3 (PUCCH format 1/1a/1b/3).In a case where the UCI is constituted from the CSI, the UCI may betransmitted on a PUCCH of a format 2/2a/2b (PUCCH format 2/2a/2b). Inorder to avoid collision with a SRS, a shortened format obtained byperforming puncturing by one symbol, and a normal format obtained by notperforming puncturing by one symbol are provided in the PUCCH format1/1a/1b. For example, in a case where simultaneous transmission of aPUCCH and a SRS in the same subframe is available, the PUCCH format1/1a/1b in a SRS subframe is transmitted in the shortened format. In acase where simultaneous transmission of a PUCCH and a SRS in the samesubframe is not available, the PUCCH format 1/1a/1b in a SRS subframe istransmitted in the normal format. At this time, even when transmissionof the SRS occurs, the SRS may not be transmitted.

As a CSI report (CSI report), a periodic CSI report and an aperiodic CSIreport are provided. The periodic CSI report is for periodicallyreporting channel state information or for reporting channel stateinformation in a case where an event condition for triggering a CSIreport is satisfied. The aperiodic CSI report is for reporting thechannel state information in response to a CSI request included in theDCI format, in a case where the CSI report is requested. The periodicCSI report is performed on a PUCCH or a PUSCH. The aperiodic CSI reportis performed on a PUSCH. In a case where an instruction is performedbased on information (CSI request) included in the DCI format, theterminal device 2 may transmit CSI which is not followed by uplink data,on the PUSCH.

An uplink reference signal (UL-RS) includes a demodulation referencesignal (DMRS) and a sounding reference signal (SRS). The demodulationreference signal is used for the base station apparatus 1 demodulating aphysical uplink control channel PUCCH and/or a physical uplink sharedchannel PUSCH. The sounding reference signal is used for the basestation apparatus 1 mainly estimating a channel state of an uplink. Asthe sounding reference signal, a periodic sounding reference signal(P-SRS) and an aperiodic sounding reference signal (A-SRS) are provided.The periodic sounding reference signal is configured so as to performperiodic transmission by a higher layer. Transmission of the aperiodicsounding reference signal is required by a SRS request included in thedownlink control information format. The uplink reference signal may bealso referred to as an uplink pilot signal or an uplink pilot channel.

A sequence for the uplink reference signals may be generated based on apseudo-random sequence. The sequence for the uplink reference signalsmay be generated based on a Zadoff-Chu sequence. The sequence for theuplink reference signals may be generated based on a Gold sequence. Thesequence for the uplink reference signals may be generated based onsubspecies or modifications of the pseudo-random sequence, theZadoff-Chu sequence, or the Gold sequence.

The periodic sounding reference signal may be also referred to as aperiodic sounding reference signal and a Trigger Type 0 soundingreference signal (Trigger Type 0 SRS). The aperiodic sounding referencesignal may be also referred to as an aperiodic sounding reference signaland a Trigger Type 1 sounding reference signal (Trigger Type 1 SRS).

The A-SRS may be classified into a signal specialized for estimating achannel of an uplink (for example, which may be also referred to as aTrigger Type 1aSRS), and a signal used for causing the base stationapparatus 1 to measure a channel state (CSI, CQI, PMI, and RI) by usingchannel reciprocity in TDD (for example, which may be also referred toas a Trigger Type 1bSRS) in coordinated communication. The DMRS isconfigured corresponding to each of the PUSCH and the PUCCH. The DMRS istime-multiplexed in the same subframe as that of the PUSCH or the PUCCH,and is transmitted.

The time multiplexing method of the DMRS may be different in a case ofthe DMRS for the PUSCH and in a case of the DMRS for the PUCCH. Forexample, regarding the DMRS for the PUSCH, only one symbol is allocatedin one slot which is constituted by seven symbols. On the contrary,regarding the DMRS for the PUCCH, three symbols are allocated in oneslot which is constituted by seven symbols.

Regarding the SRS, notification of various parameters (such as abandwidth, a cyclic shift, and a transmission subframe) is performed byhigher layer signaling. Regarding the SRS, a subframe for transmittingthe SRS is determined based on information regarding a transmissionsubframe which is included in a configuration of the SRS and of whichnotification is performed by the higher layer signaling. As theinformation regarding the transmission subframe, information (sharedinformation) configured so as to be specific to a cell, and information(dedicated information, individual information) configured so as to bespecific to a terminal device are provided. The information configuredso as to be specific to a cell includes information indicating asubframe in which the SRS shared by all terminal devices 2 in the cellis transmitted. The information configured so as to be specific to aterminal device includes information indicating periodicity and asubframe offset which functions as a subset of the subframe configuredso as to be specific to the cell. The terminal device 2 may determine asubframe (which may be also referred to as a SRS subframe and a SRStransmission subframe) for transmitting the SRS, by using the pieces ofinformation. When the terminal device 2 transmits a PUSCH in a subframein which the SRS configured so as to be specific to a cell istransmitted, the terminal device 2 may puncture a time resource of thePUSCH by symbols for transmitting the SRS, and may transmit the PUSCH byusing the punctured time resource. Thus, it is possible to avoidcollision of transmission of the PUSCH with transmission of the SRSbetween terminal devices 2. It is possible to prevent deterioration ofcharacteristics of the terminal device 2 which transmits the PUSCH. Itis possible to ensure channel estimation accuracy in the terminal device2 which transmits the SRS. Here, the information configured so as to bespecific to a terminal device may be independently configured as theP-SRS and the A-SRS.

For example, in a case where the various parameters are configured bythe higher layer signaling, a first uplink reference signal isperiodically transmitted based on the configured transmission subframe.In a case where an instruction of a transmission request is performed byusing a field (SRS request) regarding a transmission request of a seconduplink reference signal included in the downlink control informationformat, the second uplink reference signal is aperiodically transmitted.In a case where a SRS request included in certain downlink controlinformation format indicates being positive or indicates an index(value) corresponding to being positive, the terminal device 2 transmitsan A-SRS in a predetermined transmission subframe. In a case where thedetected SRS request indicates being negative or indicates an index(value) corresponding to being negative, the terminal device 2 does nottransmit an A-SRS in a predetermined subframe. Notification of theinformation (shared parameter, shared information) configured so as tobe specific to a cell is performed by using system information or adedicated control channel (DCCH). Notification of the information(dedicated parameter, individual parameter, dedicated information, andindividual information) configured so as to be specific to a terminaldevice is performed by using a common control channel (CCCH).Notification of the pieces of information may be performed by using aRRC message. Notification of the RRC message may be performed by ahigher layer.

A physical random access channel (PRACH) is a channel used fornotification of a preamble sequence. The physical random access channelhas a guard time. The preamble sequence is constituted such that 64types of sequences are prepared so as to express 6-bit information. Thephysical random access channel is used as an access unit of the terminaldevice 2 to the base station apparatus 1. The terminal device 2 uses thephysical random access channel in order to transmit a radio resourcerequest when the physical uplink control channel is not configured, inresponse to a scheduling request (SR), or in order to requesttransmission timing adjustment information (which is also referred totiming advance (TA)) to the base station apparatus 1. The transmissiontiming adjustment information is needed for causing an uplinktransmission timing to match with a reception timing window of the basestation apparatus.

Specifically, the terminal device 2 transmits a preamble sequence byusing a radio resource for the physical random access channel, which isconfigured by the base station apparatus 1. The terminal device 2 whichreceives the transmission timing adjustment information configures atransmission timing timer. The transmission timing timer tracks aneffective time of the transmission timing adjustment information whichis commonly configured by broadcast information (or which isindividually configured by the layer 3 message). The terminal device 2manages a state of the uplink in a manner that a state is set as atransmission timing adjusted state during the effective time of thetransmission timing timer (during tracking), and the state is set as atransmission timing non-adjusted state during a period which is out ofthe effective period (during stopping). The layer 3 message is a messageof a control-plane (C-plane), which is transmitted and received in aradio resource control (RRC) layer between the terminal device 2 and thebase station apparatus 1. The layer 3 message is used as having the samemeaning as RRC signaling or a RRC message. The RRC signaling may be alsoreferred to higher layer signaling or dedicated signaling.

The random access procedure includes two random access procedures of acontention based random access procedure and a non-contention basedrandom access procedure. The contention based random access procedure isa random access having a probability of collision occurring between aplurality of terminal devices 2.

The non-contention based random access procedure is a random access inwhich collision does not occur between the plurality of terminal devices2.

The non-contention based random access procedure is formed from threesteps. The terminal device 2 is notified of random access preambleassignment from the base station apparatus 1 by dedicated signaling ofthe downlink. At this time, in the random access preamble assignment,the base station apparatus 1 assigns a non-contention random accesspreamble to the terminal device 2. The random access preamble assignmentis transmitted for handover by a source base station apparatus (SourceeNB). The random access preamble assignment is subjected to signaling bya handover command which is by a target base station apparatus (TargeteNB), or is subjected to signaling by a PDCCH in a case of downlink dataarrival.

The terminal device 2 which receives the random access preambleassignment transmits a random access preamble (Message 1) on a RACH inan uplink. At this time, the terminal device 2 transmits the assignednon-contention random access preamble.

The base station apparatus 1 which receives the random access preambletransmits a random access response in the downlink data (DL-SCH:Downlink Shared Channel) to the terminal device 2. Informationtransmitted in the random access response includes a first uplink grant(random access response grant) and timing alignment information forhandover, and timing alignment information and a random access preambleidentifier for downlink data arrival. The downlink data may be alsoreferred to downlink shared channel data (DL-SCH data).

Here, the non-contention based random access procedure is applied tohandover, downlink data arrival, and positioning. The contention basedrandom access procedure is applied to an initial access from RRC_IDLE,reestablishment of RRC connection, handover, downlink data arrival, anduplink data arrival.

The random access procedure according to the embodiment is thecontention based random access procedure. An example of the contentionbased random access procedure will be described.

The terminal device 2 acquires System information block type 2 (SIB2)transmitted by the base station apparatus 1. The SIB2 corresponds to acommon configuration (common information) for all terminal devices 2 (ora plurality of terminal devices 2) in a cell. For example, the commonconfiguration includes a configuration of the PRACH.

The terminal device 2 randomly selects the number of the random accesspreamble. The terminal device 2 transmits a random access preamble(Message 1) of the selected number to the base station apparatus 1 byusing the PRACH. The base station apparatus 1 estimates a transmissiontiming of the uplink by using the random access preamble.

The base station apparatus 1 transmits a random access response (Message2) by using the PDSCH. The random access response includes plural piecesof information for the random access preamble detected by the basestation apparatus 1. For example, the plural pieces of informationinclude the number of the random access preamble, a Temporary C-RNTI, atiming advance command (TA command), and a random access response grant.

The terminal device 2 transmits (initially transmits) uplink data(Message 3) on the PUSCH scheduled by using the random access responsegrant. The uplink data includes an identifier (InitialUE-Identity orinformation indicating a C-RNTI) for identifying the terminal device 2.

In a case where decoding of uplink data fails, the base stationapparatus 1 performs an instruction of retransmission of the uplink databy using a DCI format to which a CRC parity bit scrambled by using theTemporary C-RNTI is added. In a case where the instruction ofretransmission of the uplink data is received by the DCI format, theterminal device 2 retransmits the same uplink data on a PUSCH scheduledby using the DCI format to which the CRC parity bit scrambled by usingthe Temporary C-RNTI is added.

In a case where decoding of uplink data fails, the base stationapparatus 1 may perform an instruction of retransmission of the uplinkdata by using a PHICH (NACK). In a case where the instruction ofretransmission of the uplink data is received by using the NACK, theterminal device 2 retransmits the same uplink data on the PUSCH.

The base station apparatus 1 succeeds decoding of the uplink data, andthus acquires the uplink data. Thus, it is possible to recognize whichterminal device 2 transmits the random access preamble and the uplinkdata. That is, before decoding of the uplink data is determined tosucceed, the base station apparatus 1 recognizing which terminal device2 transmits the random access preamble and the uplink data is notpossible.

In a case where Message 3 including InitialUE-Identity is received, thebase station apparatus 1 transmits a contention resolution identity(Message 4) generated based on the received InitialUE-Identity, to theterminal device 2 by using the PDSCH. In a case where the receivedcontention resolution identity matches with the transmittedInitialUE-Identity, the terminal device 2 (1) considers that contentionresolution of the random access preamble succeeds, (2) sets the value ofthe Temporary C-RNTI in the C-RNTI, (3) discards the Temporary C-RNTI,and (4) considers that the random access procedure is correctlycompleted.

In the base station apparatus 1 receives Message 3 including informationwhich indicates the C-RNTI, the base station apparatus 1 transmits a DCIformat (Message 4) to which a CRC parity bit scrambled by using thereceived C-RNTI is added, to the terminal device 2. In a case where theterminal device 2 decodes the DCI format to which the CRC parity bitscrambled by using the received C-RNTI is added, the terminal device 2(1) considers that contention resolution of the random access preamblesucceeds, (2) discards the Temporary C-RNTI, and (3) considers that therandom access procedure is correctly completed.

That is, the base station apparatus 1 performs scheduling of a PUSCH byusing the random access response grant as a part of the contention basedrandom access procedure.

The terminal device 2 transmits the uplink data (Message 3) on the PUSCHscheduled by using the random access response grant. That is, theterminal device 2 performs transmission on a PUSCH corresponding to therandom access response grant, as a part of the contention based randomaccess procedure.

The base station apparatus 1 performs scheduling of a PUSCH by using theDCI format to which a CRC scrambled by using the Temporary C-RNTI isadded, as a part of the contention based random access procedure. Thebase station apparatus 1 performs scheduling/instruction of transmissionon the PUSCH by using a PHICH (NACK), as a part of the contention basedrandom access procedure.

The terminal device 2 transmits (retransmits) the uplink data (Message3) on the PUSCH scheduled by using the DCI format to which a CRCscrambled by using the Temporary C-RNTI is added. The terminal device 2transmits (retransmits) the uplink data (Message 3) on the scheduledPUSCH, in response to reception of the PHICH. That is, the terminaldevice 2 performs transmission on the PUSCH corresponding to theretransmission of the same uplink data (transport block), as a part ofthe contention based random access procedure.

A logical channel will be described below. The logical channel is usedfor transmitting a RRC message or an information element. The logicalchannel is transmitted on a physical channel through a transportchannel.

A broadcast control channel (BCCH) is a logical channel used forbroadcasting system control information. For example, system informationor information needed for an initial access is transmitted by using thebroadcast control channel. A master information block (MIB) or SystemInformation Block Type 1 (SIB1) is transmitted by using this logicalchannel.

A common control channel (CCCH) is a logical channel used fortransmitting control information between a network, a terminal devicewhich does not have RRC connection, and a network. For example,terminal-specific control information or configuration information istransmitted by using this logical channel.

A dedicated control channel (DCCH) is a logical channel used fortransmitting dedicated control information (individual controlinformation) between a terminal device 2 having RRC connection, and anetwork in a bi-directional manner. For example, cell-specificreconfiguration information is transmitted by using this logicalchannel.

Signaling using a CCCH or a DCCH may be generically referred to RRCsignaling.

Information regarding uplink power control includes information of whichnotification as broadcast information is performed, information of whichnotification as information (shared information) shared between terminaldevices 2 in the same cell is performed, and information of whichnotification as terminal device-specific dedicated information isperformed. The terminal device 2 sets transmitted power based on onlythe information of which notification as broadcast information isperformed, or based on the information of which notification as thebroadcast information/shared information is performed, and theinformation of which notification as dedicated information is performed.

Notification of radio resource control configuration shared informationas the broadcast information (or the system information) may beperformed. Notification of the radio resource control configurationshared information as dedicated information (mobility controlinformation) may be performed.

A radio resource configuration includes a random access channel (RACH)configuration, a broadcast control channel (BCCH) configuration, apaging control channel (PCCH) configuration, a physical random accesschannel (PRACH) configuration, a physical downlink shared channel(PDSCH) configuration, a physical uplink shared channel (PUSCH)configuration, a physical uplink control channel (PUCCH) configuration,a sounding reference signal (SRS) configuration, a configurationrelating to the uplink power control, a configuration relating to anuplink cyclic prefix length, and the like. That is, the radio resourceconfiguration is configured so as to perform notification of a parameterused for generating a physical channel/physical signal. Parameters(information elements) of which notification is performed may bedifferent in a case where notification as the broadcast information isperformed, and in a case where notification as reconfigurationinformation is performed.

An information element needed for configuring the parameter relating tovarious physical channels/physical signals (PRACH, PUCCH, PUSCH, SRS, ULDMRS, CRS, CSI-RS, PDCCH, PDSCH, PSS/SSS, UERS, PBCH, PMCH, and thelike) is constituted by shared configuration information and dedicatedconfiguration information. The shared configuration information isinformation shared between terminal devices 2 in the same cell. Thededicated configuration information is configured for each of theterminal devices 2. The shared configuration information may betransmitted in the system information. In a case where reconfigurationis performed, the shared configuration information may be transmitted asthe dedicated information. The configurations include a configuration ofa parameter. The configuration of a parameter includes a configurationof a value of the parameter. In a case where the parameter is managed ina manner of a table, the configuration of a parameter includes aconfiguration of the value of an index.

Information regarding the parameter of the physical channel istransmitted to the terminal device 2 by using a RRC message. That is,the terminal device 2 configures resource assignment or transmittedpower for each physical channel, based on the received RRC message. Asthe RRC message, there are a message relating to a broadcast channel, amessage relating to a multicast channel, a message relating to a pagingchannel, a message relating to each of channels of a downlink, a messagerelating to each of channels of an uplink, and the like. Each of the RRCmessages may include an information element (IE). The informationelement may include information corresponding to a parameter. The RRCmessage may be also referred to as a message. A message class is a setof one or more message. The message may include the information element.As the information element, there are an information element relating toradio resource control, an information element relating to securitycontrol, an information element relating to mobility control, aninformation element relating to measurement, an information elementrelating to a multimedia broadcast multicast service (MBMS), and thelike. The information element may include a lower information element.The information element may be configured as the parameter. Theinformation element may be defined as control information whichindicates one or more parameters.

The information element (IE) is used for defining (designating,configuring) parameters for the system information (SI) or various typesof channels/signals/information in dedicated signaling. A certaininformation element includes one or more fields. The information elementmay be configured by one or more information elements. A field includedin the information element may be also referred to as a parameter. Thatis, the information element may include one or more types of parameters(one or more parameters). The terminal device 2 performs radio resourceassignment control, uplink power control, transmission control, and thelike, based on various parameters. The system information may be definedas the information element.

An information element may be configured in a field constituting aninformation element. A parameter may be configured in a fieldconstituting an information element.

The RRC message includes one or more information elements. A RRC messagein which a plurality of RRC messages is set is referred to as a messageclass.

As parameters which are related to uplink transmitted power control, andof which the terminal device 2 is notified by using the systeminformation, there are standard power for a PUSCH, standard power for aPUCCH, a channel loss compensation coefficient ac, a list of poweroffsets obtained by being configured for each PUCCH format, and a poweroffset of a preamble and Message 3. As parameters which are related tothe random access channel, and of which the terminal device 2 isnotified by using the system information, there are a parameter relatingto the preamble, a parameter relating to transmitted power control ofthe random access channel, and a parameter relating to transmissioncontrol of a random access preamble. The parameters are used at a timeof the initial access, or at a time of reconnection/reestablishmentafter radio link failure (RLF) occurs.

The terminal device 2 may be notified of information used forconfiguring the transmitted power, as the broadcast information. Theterminal device 2 may be notified of information for configuringtransmitted power, as the shared information. The terminal device 2 maybe notified of information for configuring transmitted power, as thededicated information (individual information).

First Embodiment

A first embodiment of the present invention will be described below. Inthe first embodiment, a communication system includes a primary basestation apparatus as the base station apparatus 1. The base stationapparatus 1 is also referred below to an access point, a point, atransmission point, a reception point, a cell, a serving cell, atransmission apparatus, a reception apparatus, a transmission station, areception station, a transmit antenna group, a transmit antenna portgroup, a receive antenna group, a receive antenna port group, acommunication apparatus, a communication terminal, and eNodeB. Theprimary base station apparatus is also referred below to a macro basestation apparatus, a first base station apparatus, a first communicationapparatus, a serving base station apparatus, an anchor base stationapparatus, a master base station apparatus, a first access point, afirst point, a first transmission point, a first reception point, amacro cell, a first cell, a primary cell, a master cell, a master smallcell. The primary cell and the master cell (master small cell) may beindependently constituted. In the first embodiment, the communicationsystem may include a secondary base station apparatus. The secondarybase station apparatus is also referred below to a remote radio head(RRH), a remote antenna, an overhang antenna, a distributed antenna, asecond access point, a second point, a second transmission point, asecond reception point, a reference node, a low power base stationapparatus (LPN: Low Power Node), a micro base station apparatus, a picobase station apparatus, a femto base station apparatus, a small basestation apparatus, a local area base station apparatus, a phantom basestation apparatus, a home (indoor) base station apparatus (Home eNodeB,Home NodeB, HeNB, HNB), a second base station apparatus, a secondcommunication apparatus, a coordinated base station apparatus group, acoordinated base station apparatus set, a coordinated base stationapparatus, a micro cell, a pico cell, a femto cell, a small cell, aphantom cell, a local area, a second cell, and a secondary cell. Thecommunication system according to the first embodiment may include aterminal device 2. The terminal device 2 is also referred below to amobile station, a mobile station apparatus, a mobile terminal, areception apparatus, a transmission apparatus, a reception terminal, atransmission terminal, a third communication apparatus, a receiveantenna group, a receive antenna port group, a transmit antenna group, atransmit antenna port group, a user device, and a user terminal (UE:User Equipment). Here, the secondary base station apparatus may beillustrated as a plurality of secondary base station apparatuses. Forexample, the primary base station apparatus and the secondary basestation apparatus may communicate with a terminal device by usingheterogeneous network arrangement, in such a manner that a portion orthe entirety of coverage of the secondary base station apparatus isincluded in coverage of the primary base station apparatus.

The communication system according to the first embodiment is configuredby the base station apparatus 1 and the terminal device 2. The singlebase station apparatus 1 may manage one or more terminal devices 2. Thesingle base station apparatus 1 may manage one or more cells (servingcell, primary cell, secondary cell, femto cell, pico cell, small cell,phantom cell). The single base station apparatus 1 may manage one ormore frequency bands (component carriers, carrier frequencies). Thesingle base station apparatus 1 may manage one or more low power basestation apparatuses (LPN: Low Power Nodes). The single base stationapparatus 1 may manage one or more home (indoor) base stationapparatuses (HeNB: Home eNodeBs). The single base station apparatus 1may manage one or more access points. Base station apparatuses 1 may beconnected to each other in a wired (optical fiber, copper wire, coaxialcable, and the like) or wireless (X2 interface, X3 interface, Xninterface, and the like) manner. That is, a plurality of base stationapparatuses 1 may communicate with each other at a high speed (withoutdelay) by using an optical fiber (Ideal backhaul), or may communicatewith each other at a low speed through the X2 interface (Non idealbackhaul). At this time, communication of various types of informationof the terminal device 2 (configuration information or channel stateinformation (CSI), function information (UE capability) of the terminaldevice 2, information for handover, and the like) may be performed. Theplurality of base station apparatuses 1 may be managed on a network. Thesingle base station apparatus 1 may manage one or more relay stationapparatus (Relay).

The communication system according to the first embodiment may realizecoordinated communication (CoMP: Coordination Multiple Points) using aplurality of base station apparatuses, low power base stationapparatuses, or home base station apparatuses. That is, thecommunication system according to the first embodiment may performdynamic point selection (DPS) in which a point (transmission pointand/or reception point) which communicates with the terminal device 2 isdynamically switched. The communication system according to the firstembodiment may perform coordinated scheduling (CS) or coordinatedbeamforming (CB). The communication system according to the firstembodiment may perform joint transmission (JT) or joint reception (JR).

A plurality of low power base station apparatuses or small cells whichare disposed so as to be close to each other may be clustered (grouped).The plurality of clustered low power base station apparatuses mayperform notification of the same configuration information. An area(coverage) of the clustered small cells may be also referred to as alocal area.

In downlink transmission, the base station apparatus 1 may be alsoreferred to as a transmission point (TP). In uplink transmission, thebase station apparatus 1 may be also referred to as a reception point(RP). The downlink transmission point and the uplink reception point mayfunction as a pathloss reference point (reference point) for measuringdownlink pathloss. The reference point for measuring pathloss may beconfigured independently from the transmission point and the receptionpoint.

The small cell, the phantom cell, or the local area cell may beconfigured as a third cell. The small cell, the phantom cell, or thelocal area cell may be reconfigured as the primary cell. The small cell,the phantom cell, or the local area cell may be reconfigured as thesecondary cell. The small cell, the phantom cell, or the local area cellmay be reconfigured as the serving cell. The small cell, the phantomcell, or the local area cell may be included in the serving cell.

The base station apparatus 1 allowed to constitute the small cell mayperform discrete reception (DRX) or discrete transmission (DTX), ifnecessary. The base station apparatus 1 allowed to constitute the smallcell may cause power of some apparatuses (for example, transmission unitor reception unit) to intermittently or quasi-stationary turn ON/OFF.

Independent identifiers (IDs: Identities) may be configured for basestation apparatuses 1 constituting a macro cell and base stationapparatuses 1 constituting a small cell. That is, identifiers of themacro cell and the small cell may be independently configured. Forexample, in a case where cell specific reference signals (CRSs) aretransmitted from the macro cell and the small cell, even whentransmission frequencies are the same as each other, and radio resourcesare the same as each other, scrambling may be performed by usingdifferent identifiers. The cell specific reference signal for the macrocell may be scrambled by using a physical layer cell ID (PCI: Physicallayer Cell Identity). The cell specific reference signal for the smallcell may be scrambled by using a virtual cell ID (VCI: Virtual CellIdentity). Scrambling may be performed in the macro cell by using thephysical layer cell ID (PCI: Physical layer Cell Identity), andscrambling may be performed in the small cell by using a global cell ID(GCI: Global Cell Identity). Scrambling may be performed in the macrocell by using a first physical layer cell ID, and scrambling may beperformed in the small cell by using a second physical layer cell ID.Scrambling may be performed in the macro cell by using a first virtualcell ID, and scrambling may be performed in the small cell by using asecond virtual cell ID. Here, the virtual cell ID may be an IDconfigured in a physical channel/physical signal. The virtual cell IDmay be an ID which is configured independently from the physical layercell ID. The virtual cell ID may be an ID used in scrambling a sequenceused in the physical channel/physical signal.

Some of physical channels/physical signals may not be transmitted in asmall cell, or a serving cell configured as the small cell, or acomponent carrier corresponding to a small cell. For example, a cellspecific reference signal (CRS) or a physical downlink control channel(PDCCH) may be not transmitted. A new physical channel/physical signalmay be transmitted in the small cell, or the serving cell configured asthe small cell, the component carrier component carrier corresponding toa small cell.

Processing or a configuration relating to a PUCCH resource of HARQresponse information will be described below. The HARQ responseinformation includes response information for PDSCH transmission, whichis shown by detection of the control channel, and response informationfor the control channel, which includes control information indicating arelease (end) of the semi-persistent scheduling (SPS). The HARQ responseinformation corresponds to ACK indicating a normal reception, NACKindicating that normal reception is not possible, and/or DTX indicatingthat transmission is not performed (reception is not performed).

The terminal device 2 transmits the HARQ response information to thebase station apparatus 1 through the PUCCH and/or PUSCH. The basestation apparatus 1 receives the HARQ response information from theterminal device 2 through the PUCCH and/or PUSCH. Thus, the base stationapparatus 1 recognizes whether or not the terminal device 2 enablescorrect reception of the PDSCH or the control channel.

Next, descriptions regarding the PUCCH resource configured in the basestation apparatus 1 will be described. The HARQ response information isspread in a SC-FDMA sample region, by using pseudo constant-amplitudezero-autocorrelation (CAZAC) sequence which is cyclically shifted. TheHARQ response information is spread into 4 SC-FDMA symbols in a slot, byusing an orthogonal cover code (OCC) which has a code length of 4.Symbols spread by two codes are mapped on two RBs having differentfrequency. In this manner, the PUCCH resource is defined by threeelements of the cyclic shift quantity, an orthogonal code, and/or themapped RB. The cyclic shift in the SC-FDMA sample region may beexpressed by phase rotation which is equally increased in the frequencydomain.

An uplink control channel region (PUCCH region) used in transmission ofthe PUCCH is RB pairs of a predetermined number, and is constituted byusing RB pairs at both ends of an uplink system bandwidth. A physicalresource used in transmission of the PUCCH is constituted from two RBshaving different frequencies in a first slot and in a second slot. Thephysical resource used in transmission of the PUCCH is indicated by m(m=0, 1, 2, . . . ). One PUCCH is allocated to any physical resourceused in transmission of the PUCCH. Thus, since one PUCCH is transmittedby using resources having different frequency, a frequency diversityeffect is obtained.

The PUCCH resource (uplink control channel logical resource) which is aresource used for transmitting a PUCCH is defined by using an orthogonalcode, a cyclic shift quantity, and/or a frequency resource. For example,a PUCCH resource in a case where three orthogonal codes of OC0, OC1, andOC2, six cyclic shift quantities of CS0, CS2, CS4, CS6, CS8, and CS10,and m indicating the frequency resource are assumed as elementsconstituting the PUCCH resource may be used. A combination of orthogonalcodes, cyclic shift quantities, and m which correspond to an nPUCCHwhich is an index indicating the PUCCH resource (uplink control channellogical resource) is defined. The index indicating the PUCCH resource isalso referred to as a PUCCH resource number. The correspondence betweenthe nPUCCH and the combination of the orthogonal codes, cyclic shiftquantities, and m is an example, and other correspondences may beprovided. For example, a correspondence may be provided so as to causethe cyclic shift quantities to be changed between continuous nPUCCHs, ora correspondence may be provided so as to cause m to be changed betweencontinuous nPUCCHs. In addition, CS1, CS3, CS5, CS7, CS9, and CS11 whichare cyclic shift quantities different from CS0, CS2, CS4, CS6, CS8, andCS10 may be used. Here, a case in which the value of m is equal to ormore than NF2 is described. The frequency resource having m which isless than NF2 means frequency resources of NF2 pieces, which arereserved in transmission of the PUCCH for performing feedback of thechannel state information.

Next, the transmission mode used in transmission of the HARQ responseinformation will be described. The HARQ response information definesvarious transmission modes (transmission methods). The transmission modeused in transmission of the HARQ response information is determined byinformation or a configuration specific to the base station apparatus 1,information or a configuration specific to the terminal device 2, and/orinformation regarding a PDCCH which corresponds to the HARQ responseinformation, a configuration of a higher layer, and the like. Thetransmission mode used in transmission of the HARQ response informationcorresponds to HARQ response information bundling (HARQ-ACK bundling),and HARQ response information multiplexing (HARQ-ACK multiplexing).

Plural pieces of HARQ response information may be transmitted in acertain uplink subframe. The number of pieces of HARQ responseinformation transmitted in the certain uplink subframe is determined bythe number of code words (transport blocks) transmitted on one PDSCH, asubframe configuration, and/or a configuration of carrier aggregation.For example, one PDSCH may transmit two code words which are themaximum, through Multi Input Multi Output (MIMO) transmission, and HARQresponse information is generated with respect to each of the codewords. For example, in TDD, the type of a subframe is determined basedon the subframe configuration. Thus, in a case where HARQ responseinformation in response to transmission of PDSCHs in a plurality ofdownlink subframes is transmitted in a certain uplink subframe, pluralpieces of HARQ response information corresponding to code words of thePDSCHs in the downlink subframes are generated. For example, in a casewhere carrier aggregation by a plurality of cells is configured, pluralpieces of HARQ response information corresponding to code words ofPDSCHs in the cells are generated.

In a case where plural pieces of HARQ response information aretransmitted in a certain uplink subframe, the pieces of HARQ responseinformation are transmitted by using HARQ response information bundlingand/or HARQ response information multiplexing.

In the HARQ response information bundling, a logical AND operation isperformed on a plural pieces of HARQ response information. The HARQresponse information bundling may be performed in various units. Forexample, the HARQ response information bundling is performed on all codewords in a plurality of downlink subframes. The HARQ responseinformation bundling is performed on all code words in one downlinksubframe. The HARQ response information bundling allows the informationquantity of the HARQ response information to be reduced. In the HARQresponse information multiplexing, multiplexing is performed on pluralpieces of HARQ response information. Information subjected to the HARQresponse information bundling may be subjected to multiplexing. In thefollowing descriptions, information subjected to the HARQ responseinformation bundling is also simply referred to HARQ responseinformation.

A PUCCH for transmitting the HARQ response information may define pluraltypes of formats. As a format of the PUCCH for transmitting the HARQresponse information, PUCCH format 1a, PUCCH format 1b, PUCCH format 1bfor selecting a channel (PUCCH 1b with channel selection), PUCCH format3, and the like are provided. The transmission mode used in transmissionof the HARQ response information also includes the PUCCH format to betransmitted.

The PUCCH format 1a is a PUCCH format used for transmitting 1-bit HARQresponse information. In a case where the HARQ response information istransmitted in the PUCCH format 1a, one PUCCH resource is assigned, andthe HARQ response information is transmitted by using the assigned PUCCHresource.

The PUCCH format 1b is a PUCCH format used for transmitting 2-bit HARQresponse information. In a case where the HARQ response information istransmitted in the PUCCH format 1b, one PUCCH resource is assigned, andthe HARQ response information is transmitted by using the assigned PUCCHresource.

The PUCCH format 1b for performing channel selection is a PUCCH formatused for transmitting 2 pieces, 3 pieces, or 4 pieces of HARQ responseinformation. Regarding the PUCCH format used for transmitting 2 pieces,3 pieces, or 4 pieces of HARQ response information, 2, 3, or 4 PUCCHresources (channels) are configured. In the channel selection, any of aplurality of configured PUCCH resources is selected and the selectedPUCCH resource is used as a portion of information. 2-bit informationwhich can be transmitted by using the selected PUCCH resource is alsoused as a portion of the information. Since the 2-bit information issubjected to QPSK modulation, the 2-bit information is transmitted asone symbol. That is, in the PUCCH format 1b for performing the channelselection, 2 pieces, 3 pieces, or 4 pieces of HARQ response informationare transmitted by using a combination of a PUCCH resource selected froma plurality of configured PUCCH resources, and 2-bit information whichcan be transmitted by using the selected PUCCH resource. The combinationand each piece of the HARQ response information are defined in advance.The HARQ response information corresponds to ACK, NACK, DTX, orNACK/DTX. The NACK/DTX indicates NACK or DTX. For example, in a casewhere carrier aggregation is not configured, 2 pieces, 3 pieces, or 4pieces of HARQ response information correspond to HARQ responseinformation in response to PDSCH transmission in which transmission isperformed in 2, 3, or 4 downlink subframes.

The PUCCH format 3 is a PUCCH format used for transmitting HARQ responseinformation which has 20 bit as the maximum. One PUCCH resource isconfigured in the PUCCH format 3. The one PUCCH resource in the PUCCHformat 3 is for transmitting the HARQ response information which has 20bit as the maximum. The PUCCH resource in the PUCCH formats 1a/1b andthe PUCCH resource in the PUCCH format 3 are independent. For example,the base station apparatus 1 preferably performs configuring so as toconstitute the PUCCH resource in the PUCCH formats 1a/1b and the PUCCHresource in the PUCCH format 3 by using different physical resources(that is, two RBs for constituting a physical resource used intransmission of a PUCCH).

In a case where HARQ response information is transmitted on a PUCCH, theHARQ response information is mapped and transmitted on the PUCCHresource which is explicitly and/or implicitly configured. The PUCCHresource used in transmission of the HARQ response information isuniquely determined by information or a configuration specific to thebase station apparatus 1, information or a configuration specific to theterminal device 2, and/or information regarding a PDCCH or an EPDCCHwhich corresponds to the HARQ response information, and the like. Forexample, a PUCCH resource number indicating PUCCH resources used intransmission of the HARQ response information is calculated by usingparameters included in the pieces of information and/or parametersobtained from the pieces of information, and a predetermined method(operation).

In a general FDD cell (for example, FDD cell in which carrieraggregation is not performed, or FDD cell in which carrier aggregationis performed only with another FDD cell), HARQ response informationwhich corresponds to a PDSCH transmitted in a downlink componentcarrier, or a PDCCH indicating a release of downlink semi-persistentscheduling (SPS) (SPS release) in a subframe (n−4) is transmitted by anuplink component carrier corresponding to the downlink componentcarrier. The HARQ response information corresponding to the PDSCHallocated in a subframe n is transmitted by using a PUCCH/PUSCHallocated in a subframe (n+4). That is, after the terminal device 2receives a PDSCH in a certain subframe, the terminal device 2 transmitsHARQ response information corresponding to the PDSCH, to the basestation by using a PUCCH/PUSCH after four subframes. Thus, the basestation can receive the HARQ response information which has beentransmitted corresponding to the PDSCH, from the terminal device 2, anddetermine whether or not the PDSCH is retransmitted based on informationof ACK/NACK.

That is, in FDD cells, in a case where one serving cell is configuredfor the terminal device 2, or in a case where serving cells of which thenumber is more than one are configured for the terminal device 2, andthe primary cell is the FDD cell, when PDSCH transmission in which theterminal device 2 has been set as a target in the subframe (n−4), andthe HARQ response information is given is detected, the terminal device2 transmits the HARQ response information in the subframe n.

In a general TDD cell (for example, TDD cell in which carrieraggregation is not performed, or TDD cell in which carrier aggregationis performed only with another TDD cell), it is not necessary that anuplink subframe after four subframes from a downlink subframe isconfigured. Thus, an uplink subframe corresponding to the downlinksubframe is defined. In an example of details of HARQ responseinformation multiplexing in PDSCH transmission, which is shown by aPDCCH or an EPDCCH, a downlink association set illustrated in FIG. 6 isused. FIG. 6 is a diagram illustrating an example of an index K: {k₀,k₁, . . . , k_(M-1)} of the downlink association set. HARQ responseinformation included in a PUCCH/PUSCH allocated in the subframe ncorresponds to a PDSCH shown by detecting a PDCCH associated in asubframe (n−k_(i)), or to a PDCCH indicating a release of the downlinkSPS in the subframe (n−k_(i)). In other words, HARQ response informationwhich corresponds to the PDSCH shown in the subframe n by detecting aPDCCH, or to the PDCCH indicating a release of the downlink SPS isincluded in a PUCCH/PUSCH in a subframe (n+k_(i)), and is transmitted.

That is, in TDD cells, in a case where one serving cell is configuredfor the terminal device 2, or in a case where serving cells of which thenumber is more than one are configured for the terminal device 2, andall UL-DL configurations are the same, when PDSCH transmission in whichthe terminal device 2 has been set as a target in the subframe (n−k),and the HARQ response information is given is detected, the terminaldevice 2 transmits the HARQ response information in the uplink subframen. Here, k belongs to a set K (k∈K), and the set K is defined by usingthe figure in FIG. 6.

FIG. 4 is a diagram 400 illustrating an example of HARQ responseinformation multiplexing in PDSCH transmission shown by the PDCCH 412 ina TDD cell 414. FIG. 4 illustrates PUCCH resources used for HARQresponse information multiplexing in a case where HARQ responseinformation is transmitted in four downlink subframes (4 bits) by usingthe PUCCH format 1b for performing channel selection. FIG. 4 illustratesa PUCCH resource 410 extracted from a subframe (n−k_(i)) 416 a. 416 b,416 c, and 416 d in a certain uplink subframe n. Here, each subframe(n−k_(i)), i.e., each of 416 a, 416 b, 416 c, and 416 d, indicates asubframe ahead of k_(i) pieces from the subframe n. If it is assumedthat the number of subframes (bits) for performing the HARQ responseinformation multiplexing is M, i is an integer which is equal to or morethan 0 and equal to or less than (M−1). That is, in FIG. 4, in thesubframe n, 4-bit HARQ response information is transmitted by usingPUCCH resources 410 extracted from four downlink subframes (subframe(n−k₀) 416 a, subframe (n−k₁) 416 b, subframe (n−k₂) 416 c, and subframe(n−k₃) 416 d). The value of M, and the value of k_(i) are defined by thenumber of the subframe n and the subframe configuration. Here, a timewindow including a set of subframes expressed by (n−k) (k corresponds toeach k_(i) included in K) may be referred to as a bundling window (see,e.g., elements 810, 830 in FIG. 8). The number of subframes in thebundling window corresponds to M, and the subframes in the bundlingwindow means subframes from a subframe (n−k₀) to a subframe (n−k_(M-1)).The size (time length) of the bundling window may vary depending on thesubframe n having the corresponding uplink subframe. The size of thebundling window may vary depending on the subframe constitution (UL/DLconfiguration) in TDD.

The PUCCH resource used for the HARQ response information in PDSCHtransmission shown by the PDCCH is determined based on at least aparameter N⁽¹⁾ _(PUCCH) configured in a higher layer, and the first CCEnumber n_(CCE) used for transmitting the PDCCH associated with the HARQresponse information. As illustrated in FIG. 4, indices of PUCCHresources used for the HARQ response information in PDSCH transmissionshown by the PDCCH are given in order of OFDM symbols 430 on whichn_(CCE) is mapped in subframes thereof. That is, block interleaving isperformed between subframes which are subjected to HARQ responseinformation multiplexing. Thus, since the number of OFDM symbols 430constituting a PDCCH region which is a region on which the PDCCH may bemapped may be set for each subframe, a probability of the PUCCHresources being integrated in front becomes high. Accordingly, the PUCCHresources used for the HARQ response information are efficiently used.

FIG. 5 is a diagram illustrating an example of HARQ response informationmultiplexing in PDSCH transmission shown by an EPDCCH 512. FIG. 5illustrates PUCCH resources used for HARQ response informationmultiplexing in a case where HARQ response information is transmitted infour downlink subframes (4 bits) by using the PUCCH format 1b forperforming channel selection. FIG. 5 illustrates a PUCCH resource 510extracted from a subframe (n−k_(i)) 516 a, 516 b, 516 c and 516 d, in acertain uplink subframe n. Here, the each subframe (n−k_(i)), i.e., eachof 516 a, 516 b, 516 c, and 516 d, indicates a subframe ahead of k_(i)pieces from the subframe n. If it is assumed that the number ofsubframes (bits) for performing the HARQ response informationmultiplexing is M, i is an integer which is equal to or more than 0 andequal to or less than (M−1). That is, in FIG. 5, in the subframe n,4-bit HARQ response information is transmitted by using PUCCH resources510 extracted from four downlink subframes (subframe (n−k₀) 516 a,subframe (n−k₁) 516 b, subframe (n−k₂) 516 c, and subframe (n−k₃) 516d). The value of M, and the value of k_(i) are defined by the number ofthe subframe n and the subframe configuration.

The PUCCH resource used for the HARQ response information in PDSCHtransmission shown by the EPDCCH 512 is determined based on at least aparameter N^((e1)) _(PUCCH) configured in a higher layer, and the firstCCE number n_(ECCE) used for transmitting the EPDCCH 512 associated withthe HARQ response information. As illustrated in FIG. 5, indices ofPUCCH resources 510 used for the HARQ response information in PDSCHtransmission shown by the EPDCCH 512 are given in order from an EPDCCHmapped on the subframe (n−k₀) 530. (Note: the label “SUBFRAME n−k₀” at530 in FIG. 5 indicates PUCCH resources corresponding to “SUBFRAMEn−k₀”, whereas the label “SUBFRAME n−k₀” at 516 a indicates a specificsubframe “SUBFRAME n−k0”.)

In the following descriptions, details of the HARQ response informationmultiplexing in PDSCH transmission shown by the PDCCH or the EPDCCH willbe described.

In an example of the details of the HARQ response informationmultiplexing in PDSCH transmission shown by the PDCCH or the EPDCCH, adownlink association set illustrated in FIG. 6, and an operation ofPUCCH resources which are used in transmission of the HARQ responseinformation. The operation of PUCCH resources is illustrated in FIG. 7.FIG. 6 is a diagram illustrating an example of an index K: {k₀, k₁, . .. , k_(M-1)} of the downlink association set. FIG. 7 is a diagramillustrating an example of an expression for applying PUCCH resourcesused in transmission of the HARQ response information.

In a case where the HARQ response information multiplexing is performedin the subframe n having M which is more than 1, n⁽¹⁾ _(PUCCH, i)indicating a PUCCH resource extracted from the subframe (n−k_(i)), andHARQ-ACK(i) indicating a response of ACK/NACK/DTX from the subframe(n−k_(i)) will be described as follows. M is the number of elements inthe set K defined in FIG. 6. M is the number obtained based on the HARQresponse information which is subjected to multiplexing. k_(i) isincluded in the set K, and i is from 0 to (M−1). For example, in a casewhere an uplink-downlink configuration 610 is 2, the set K 620 in thesubframe 2 (630) is {8, 7, 4, 6}, M is 4, k₀ is 8, k₁ is 7, k₂ is 4, andk₃ is 6.

PUCCH resources for a PDCCH which indicates PDSCH transmission shown bydetecting the PDCCH associated in the subframe (n−k_(i)) or release ofdownlink semi-persistent scheduling (downlink SPS) (SPS release) in thesubframe (n−k_(i)) are given by the expression (a) in FIG. 7. n_(CCE, i)is the number (index) of the first CCE used for transmitting the PDCCHassociated in the subframe (n−k_(i)), and N⁽¹⁾ _(PUCCH) is a parameterconfigured in the higher layer. N^(DL) _(RB) is the number of resourceblocks in a downlink, and N^(RB) _(sc) is the number of subcarriers pera resource block.

PUCCH resources for an EPDCCH which indicates PDSCH transmission shownby detecting the EPDCCH associated in the subframe (n−k_(i)) or releaseof downlink semi-persistent scheduling (downlink SPS) (SPS release) inthe subframe (n−k_(i)) are given by the expression (b-1) and theexpression (b-2) in FIG. 7. In a case where an EPDCCH set(EPDCCH-PRB-set) q is configured in distributed transmission, theexpression (b-1) in FIG. 7 is used for the PUCCH resources. In a casewhere the EPDCCH set (EPDCCH-PRB-set) q is configured in localizedtransmission, the expression (b-2) in FIG. 7 is used for the PUCCHresources. n_(ECCE, q) is the number (index) of the first CCE used fortransmission of DCI allocation which is associated in the subframe(n−k_(i)). That is, the number of the CCE is the smallest index of anECCE used for constituting the EPDCCH. N^((e1)) _(PUCCH, q) is aparameter in the EPDCCH set q, which is configured in the higher layer.N^(ECCE, q) _(RB) is the total number of resource blocks configured forthe EPDCCH set q in the subframe (n−k_(i)).

That is, M pieces of PUCCH resources are given in the subframe n. The Mpieces of PUCCH resources are used for transmitting a PUCCH having thePUCCH format 1b for performing channel selection. For example, in a casewhere an uplink-downlink configuration 610 is 2 (in FIG. 6), four PUCCHresources are given in the subframe 2 (630). The four PUCCH resourcesare used for transmitting a PUCCH having the PUCCH format 1b forperforming channel selection.

Here, a subframe indicated by each set K in the downlink association set620 illustrated in FIG. 6 corresponds to a downlink subframe, a specialsubframe, and/or a flexible subframe (see elements 314, 316, 318 in FIG.3). Thus, even in a case where the flexible subframe is configured inaddition to the downlink subframe and the special subframe, it ispossible to efficiently transmit the HARQ response information for thePDSCH, which is transmitted in the downlink subframe, the specialsubframe, and/or the flexible subframe.

In the following descriptions, an uplink reference UL-DL configurationand a downlink reference UL-DL configuration will be described.

If the base station apparatus 1 or the terminal device 2 satisfies acertain condition, one of the base station apparatus 1 and the terminaldevice 2 may perform configuring as an uplink reference UL-DLconfiguration, and another may perform configuring as a downlinkreference UL-DL configuration. For example, the terminal device 2 mayreceive two pieces of information regarding a first configuration, andinformation regarding a second configuration, and may performconfiguring of an uplink reference UL-DL configuration and a downlinkreference UL-DL configuration. A DCI format associated with an uplink(for example, DCI format 0/4) may be transmitted in a downlink subframeconfigured in the uplink reference UL-DL configuration.

The uplink reference UL-DL configuration and the downlink referenceUL-DL configuration may be configured by using the same table. In a casewhere indices of the uplink reference UL-DL configuration and thedownlink reference UL-DL configuration are configured based on the sametable, the uplink reference UL-DL configuration and the downlinkreference UL-DL configuration are preferably configured so as to haveindices different from each other. That is, regarding the uplinkreference UL-DL configuration and the downlink reference UL-DLconfiguration, subframe patterns different from each other arepreferably configured.

In a case where a plurality of TDD UL/DL configurations are shown forone serving cell (primary cell, secondary cell), any one of the TDDUL/DL configurations may be configured as an uplink reference UL-DLconfiguration, and another one TDD UL/DL configuration may be configuredas a downlink reference UL-DL configuration, in accordance withconditions. The uplink reference UL-DL configuration may be at leastused for determining a correspondence between a subframe in which aphysical downlink control channel is allocated, and a subframe in whicha physical uplink shared channel corresponding to a physical downlinkcontrol channel is allocated. The uplink reference UL-DL configurationmay be different from an actual transmission direction of a signal (thatis, uplink or downlink). The downlink reference UL-DL configuration maybe at least used for determining a correspondence between a subframe inwhich a physical downlink shared channel is allocated, and a subframe inwhich HARQ response information corresponding to the physical downlinkshared channel is transmitted. The downlink reference UL-DLconfiguration may be different from an actual transmission direction ofa signal (that is, uplink or downlink). That is, the uplink referenceUL-DL configuration is used for specifying (selecting, determining) acorrespondence between a subframe n in which a PDCCH/EPDCCH/PHICH isallocated, and a subframe (n+k) in which a PUSCH corresponding to thePDCCH/EPDCCH/PHICH is allocated. In a case where one primary cell isconfigured, or in a case where one primary cell and one secondary cellare configured, and an uplink reference UL-DL configuration for theprimary cell and an uplink reference UL-DL configuration for thesecondary cell are the same, the corresponding uplink reference UL-DLconfiguration in each of the two serving cells is used for determining acorrespondence between a subframe in which a PDCCH/EPDCCH/PHICH isallocated, and a subframe in which a PUSCH corresponding to thePDCCH/EPDCCH/PHICH is allocated. The downlink reference UL-DLconfiguration is used for specifying (selecting, determining) acorrespondence between a subframe n in which a PDSCH is allocated, and asubframe (n+k) in which HARQ response information corresponding to thePDSCH is transmitted. In a case where one primary cell is configured, orin a case where one primary cell and one secondary cell are configured,and a downlink reference UL-DL configuration for the primary cell and adownlink reference UL-DL configuration for the secondary cell are thesame, the corresponding downlink reference UL-DL configuration in eachof the two serving cells is used for specifying (selecting, determining)a correspondence between a subframe n in which a PDSCH is allocated, anda subframe (n+k) in which HARQ response information corresponding to thePDSCH is transmitted.

As an example in which the downlink reference UL-DL configuration isconfigured in the terminal device 2, there is a case where two or moreTDD cells are configured in the terminal device 2, and UL-DLconfigurations of at least two serving cells are configured so as to bedifferent from each other. At this time, the downlink reference UL-DLconfiguration (in column 1010) of a serving cell is determined from acombination of either of the primary cell and the secondary cell (incolumn 1020), and a set number (in column 1030) defined in FIG. 10, anda pair of a primary cell UL-DL configuration and a secondary cell UL-DLconfiguration. At this time, HARQ response information included in thePUCCH/PUSCH which is allocated in the subframe n corresponds to a PDSCHshown by detecting a PDCCH associated in a subframe (n−k), or to a PDCCHindicating a release of downlink SPS in the subframe (n−k). Here,regarding k, correlation is performed by using a value defined in FIG.6, from the downlink reference UL-DL configuration.

That is, in TDD cells, in a case where serving cells of which the numberis more than one are configured in the terminal device 2, at least twoserving cells have UL-DL configurations different from each other, andthe above serving cell is the primary cell, the UL-DL configuration ofthe primary cell is a downlink reference UL-DL configuration of theabove serving cell.

That is, in TDD cells, in any of the following cases, the downlinkreference UL-DL configuration of the above serving cell is defined inFIG. 10. The following cases are a case where serving cells of which thenumber is more than one are configured in the terminal device 2, atleast two serving cells have UL-DL configurations different from eachother, the above serving cell is the secondary cell, and thus a pair ofthe primary cell UL-DL configuration and the secondary cell UL-DLconfiguration belongs to a set 1 in FIG. 10; a case where monitoring ofa PDCCH/EPDCCH from other serving cells is not configured for schedulingof the above serving cell, in the terminal device 2, and the pair of theprimary cell UL-DL configuration and the secondary cell UL-DLconfiguration belongs to a set 2 or a set 3 in FIG. 10; and a case wheremonitoring of a PDCCH/EPDCCH from other serving cells is configured forscheduling of the above serving cell, in the terminal device 2, and thepair of the primary cell UL-DL configuration and the secondary cellUL-DL configuration belongs to a set 4 or a set 5 in FIG. 10.

That is, in TDD cells, in a case where serving cells of which the numberis more than one are configured in the terminal device 2, at least twoserving cells have UL-DL configurations different from each other, andthe downlink reference UL-DL configuration of at least one serving cellis TDD UL-DL configuration 5, the terminal device 2 does not expect thatserving cells of which the number is more than 2 are configured.

That is, in TDD cells, in a case where serving cells of which the numberis more than one are configured for the terminal device 2, and at leasttwo serving cells have UL-DL configurations different from each other,when PDSCH transmission in which the terminal device 2 has been set as atarget for a serving cell c in the subframe (n−k), and the HARQ responseinformation is given is detected, the terminal device 2 transmits theHARQ response information in the uplink subframe n. Here, k belongs to aset K_(c) (k∈K_(c)), and the set K is defined by using the figure inFIG. 6. Here, the set K_(c) includes the value of k belonging to the setK, so as to be for the subframe (n−k) corresponding to a downlinksubframe or a special subframe for the serving cell c. Here, the UL-DLconfiguration in FIG. 6 refers to a downlink reference UL-DLconfiguration of this FDD cell.

In the following descriptions, a transmission timing of HARQ responseinformation in a state of assuming a case where a plurality of cells towhich different frame structure types are applied are aggregated.

Here, integration of the plurality of cells to which different framestructure types are applied includes, for example, a case where a cellin which a frame structure type is Type 1 (FDD), and a cell in which aframe structure type is Type 2 (TDD) are aggregated. The integration ofthe plurality of cells to which different frame structure types areapplied includes, for example, a case where a plurality of cells inwhich a frame structure type is Type 1 (FDD), and a plurality of cellsin which a frame structure type is Type 2 (TDD) are aggregated. That is,the integration of the plurality of cells to which different framestructure types are applied includes, for example, a case where one ormore cells in which a frame structure type is Type 1 (FDD), and one ormore cells in which a frame structure type is Type 2 (TDD) areaggregated. The descriptions for the frame structure type are anexample, and may be similarly applied to a case where Type 3 or Type 4is defined. A cell which is the primary cell of TDD is referred to as aTDD primary cell below. A cell which is the secondary cell of TDD isreferred to as a TDD secondary cell below. A cell which is the primarycell of FDD is referred to as an FDD primary cell below. A cell which isthe secondary cell of FDD is referred to as an FDD secondary cell below.In a case where carrier aggregation is configured, the terminal device 2transmits a PUCCH in the primary cell, and the base station apparatus 1receives the PUCCH from the terminal device 2 in the primary cell. Theterminal device 2 is not required for transmitting the PUCCH in thesecondary cell, and the base station apparatus 1 is not required forreceiving the PUCCH from the terminal device 2 in the secondary cell.

An example of the transmission timing of the HARQ response informationin an FDD cell, in a case where the primary cell is a TDD cell will bedescribed.

Regarding all UL-DL configurations, an uplink subframe is configured inthe subframe 2. All pieces of HARQ response information corresponding toa PDSCH detected in an FDD secondary cell or a PDCCH indicating arelease of downlink SPS in a case where the primary cell is a TDD cellare transmitted at a timing for the subframe 2. That is, thetransmission timing of HARQ response information in an FDD secondarycell which performs carrier aggregation with a TDD primary cell causetransmission to be performed in accordance with TDD UL-DL configuration5.

That is, in a case where serving cells of which the number is more thanone are configured in the terminal device 2, and the primary cell is aTDD cell, the downlink reference UL-DL configuration of this FDD cell isTDD UL-DL configuration 5, and the terminal device 2 does not expectthat serving cells of which the number is more than two are configured.

That is, in FDD cells, in a case where serving cells of which the numberis more than one are configured in the terminal device 2, and theprimary cell is a TDD cell, when PDSCH transmission in which theterminal device 2 has been set as a target in the subframe (n−k), andHARQ response information is given is detected, the terminal device 2transmits the HARQ response information in the uplink subframe n. Here,k belongs to the set K (k∈K), and the set K is defined by the figure inFIG. 6. Here, the UL-DL configuration in FIG. 6 refers to a downlinkreference UL-DL configuration of this FDD cell.

An example of a transmission timing of HARQ response information in anFDD cell, in a case where the primary cell is a TDD cell will bedescribed.

In the above-described example, the transmission timing of the HARQresponse information in a case of assuming that all TDD UL-DLconfigurations are used in the TDD primary cell is described, andconfiguring is performed in advance, at the transmission timing of theHARQ response information for TDD UL-DL configuration 5. Thetransmission timing of the HARQ response information may be set in ahigher layer. For example, in a case where a use of the TDD UL-DLconfiguration is limited to 0, 1, or 2, the downlink reference UL-DLconfiguration may be set to be 2 by a higher layer. That is, thedownlink reference UL-DL configuration for determining the transmissiontiming of HARQ response information in an FDD secondary cell whichperforms carrier aggregation with a TDD primary cell is configured inthe higher layer.

That is, in FDD cells, in a case where serving cells of which the numberis more than one are configured in the terminal device 2, and theprimary cell is a TDD cell, the downlink reference UL-DL configurationof this FDD cell is configured in the higher layer.

That is, in FDD cells, in a case where serving cells of which the numberis more than one are configured in the terminal device 2, the primarycell is a TDD cell, and thus at least one serving cell has the TDD UL-DLconfiguration 5, the terminal device 2 does not expect that servingcells of which the number is more than 2 are configured.

That is, in FDD cells, in a case where serving cells of which the numberis more than one are configured in the terminal device 2, and theprimary cell is a TDD cell, when PDSCH transmission in which theterminal device 2 has been set as a target in the subframe (n−k), andHARQ response information is given is detected, the terminal device 2transmits the HARQ response information in the uplink subframe n. Here,k belongs to the set K (k∈K), and the set K is defined by the figure inFIG. 6. Here, the UL-DL configuration in FIG. 6 refers to a downlinkreference UL-DL configuration of this FDD cell.

An example of a transmission timing of HARQ response information in anFDD cell, in a case where the primary cell is a TDD cell will bedescribed.

HARQ response information corresponding to a PDSCH detected in an FDDsecondary cell or a PDCCH indicating a release of downlink SPS in a casemay be transmitted by using a PUCCH. The PUCCH is transmitted from anuplink subframe of the TDD primary cell. That is, a downlink referenceUL-DL configuration for determining a transmission timing of HARQresponse information of the FDD secondary cell which performs carrieraggregation with the TDD primary cell tracks the TDD UL-DL configurationof the primary cell.

That is, in FDD cells, in a case where serving cells of which the numberis more than one are configured in the terminal device 2, and theprimary cell is a TDD cell, the downlink reference UL-DL configurationof this FDD cell corresponds to the TDD UL-DL configuration of theprimary cell.

That is, in FDD cells, in a case where serving cells of which the numberis more than one are configured in the terminal device 2, the primarycell is a TDD cell, and thus at least one serving cell has the TDD UL-DLconfiguration 5, the terminal device 2 does not expect that servingcells of which the number is more than 2 are configured.

That is, in FDD cells, in a case where serving cells of which the numberis more than one are configured in the terminal device 2, and theprimary cell is a TDD cell, when PDSCH transmission in which theterminal device 2 has been set as a target in the subframe (n−k), andHARQ response information is given is detected, the terminal device 2transmits the HARQ response information in the uplink subframe n. Here,k belongs to the set K (k∈K), and the set K is defined by the figure inFIG. 6. Here, the UL-DL configuration in FIG. 6 refers to a downlinkreference UL-DL configuration of this FDD cell.

An example of a transmission timing of HARQ response information in anFDD cell, in a case where the primary cell is a TDD cell will bedescribed.

In a case where the HARQ response information of the FDD cell istransmitted in accordance with the TDD UL-DL configuration of the TDDprimary cell, since the TDD primary cell may not be correlated in asubframe functioning as an uplink subframe, scheduling of the PDSCH orthe PDCCH indicating the release of downlink SPS is not performed in thesubframe even in the FDD secondary cell. A table in which the PDSCH, thePDCCH indicating the release of downlink SPS, and the transmissiontiming of the HARQ response information are correlated with each otheris also used in the subframe which functions as the uplink subframe.FIG. 9 illustrates an example of the transmission timing of the HARQresponse information, which corresponds to each of a PDSCH of the FDDsecondary cell and a PDCCH indicating the release of downlink SPS, in acase of the TDD primary cell. It is possible to also transmit the PDSCHand the PDCCH indicating the release of downlink SPS, in the FDDsecondary cell even in a subframe which functions as an uplink subframein the TDD primary cell by using the transmission timing defined in FIG.9. In addition, the HARQ response information corresponding to the PDSCHand the PDCCH is transmitted in the uplink subframe of the TDD primarycell. That is, the downlink reference UL-DL configuration 910 fordetermining the transmission timing of the HARQ response information inan FDD cell tracks the TDD UL-DL configuration of the primary cell, andthe transmission timing is determined by using the table of thetransmission timing of the HARQ response information for the FDDsecondary cell which performs the carrier aggregation with the TDDprimary cell.

That is, in FDD cells, in a case where serving cells of which the numberis more than one are configured in the terminal device 2, and theprimary cell is a TDD cell, the downlink reference UL-DL configurationof this FDD cell corresponds to the TDD UL-DL configuration of theprimary cell.

In FDD cells, in a case where serving cells of which the number is morethan one are configured in the terminal device 2, the primary cell is aTDD cell, and thus at least one serving cell has TDD UL-DL configuration5, the terminal device 2 does not expect that serving cells of which thenumber is more than 2 are configured.

In FDD cell, in a case where serving cells of which the number is morethan one are configured in the terminal device 2, the primary cell is aTDD cell, when PDSCH transmission in which the terminal device 2 hasbeen set as a target in the subframe (n−k), and the HARQ responseinformation is given is detected, the terminal device 2 transmits theHARQ response information in the uplink subframe n. Here, k belongs to aset K (k∈K), and the set K is defined by using the figure in FIG. 9.Here, the UL-DL configuration 910 in FIG. 9 refers to the downlinkreference UL-DL configuration of this FDD cell.

An example of the transmission timing of the HARQ response informationin an FDD cell, in a case where the primary cell is a TDD cell will bedescribed.

In a case where the primary cell is an FDD cell, uplink resources(uplink component carriers) are configured in all subframes. Regarding atransmission timing of HARQ response information corresponding to aPDSCH or a PDCCH indicating a release of downlink SPS, transmission maybe performed in accordance with the transmission timing of the HARQresponse information, which is configured in an FDD cell. That is, evenin the TDD cell, in a case where the primary cell is an FDD cell, thetransmission timing is the same as the transmission timing of HARQresponse information in a case where one FDD cell is configured, or in acase where carrier aggregation for only FDD cells is performed. That is,the terminal device 2 transmits a PDSCH in a certain subframe, and thentransmits HARQ response information corresponding to the PDSCH, to thebase station apparatus 1 on a PUCCH/PUSCH after 4 subframes.

That is, in TDD cells, serving cells of which the number is more thanone are configured in the terminal device 2, at least two serving cellshave frame constitution types different from each other, and the primarycell is an FDD cell, when PDSCH transmission in which the terminaldevice 2 has been set as a target in the subframe (n−4), and the HARQresponse information is given is detected, the terminal device 2transmits the HARQ response information in the subframe n.

An example of the transmission timing of the HARQ response informationin a TDD cell, in a case where the primary cell is an FDD cell will bedescribed.

Even when the primary cell is an FDD cell, and HARQ response informationcorresponding to a PDSCH transmitted in a TDD cell, or a PDCCHindicating the release of downlink SPS is transmitted in the FDD primarycell, transmission is performed by using a transmission timing of theTDD serving cell. That is, the terminal device 2 receives a PDSCH in thesubframe n, and then transmits HARQ response information correspondingto the PDSCH, to the base station apparatus 1 by using on a PUCCH/PUSCHallocated in the subframe (n+k).

In a case where an FDD cell is the primary cell, and a TDD cell is thesecondary cell, the base station apparatus 1 receives the HARQ responseinformation corresponding to the PDSCH which has been transmitted in theTDD cell, in a subframe after 4 subframes in which the PDSCH has beentransmitted. In a case where the FDD cell is the primary cell, and theTDD cell is the secondary cell, the terminal device 2 transmits the HARQresponse information corresponding to the PDSCH which has beentransmitted in the TDD cell, in a subframe after 4 subframes from asubframe in which the PDSCH has been transmitted in the TDD cell.

That is, in TDD cells, in a case where serving cells of which the numberis more than one are configured for the terminal device 2, and theprimary cell is an FDD cell, when PDSCH transmission in which theterminal device 2 has been set as a target in the subframe (n−k), andHARQ response information is given is detected, the terminal device 2transmits the HARQ response information in the uplink subframe n. Here,k belongs to the set K (k∈K), and the set K is defined by the figure inFIG. 6. Here, the UL-DL configuration in FIG. 6 refers to a downlinkreference UL-DL configuration of this TDD cell.

Thus, even when carrier aggregation between the TDD cell and the FDDcell is performed, the terminal device 2 can transmit the HARQ responseinformation corresponding to the PDSCH or the PDCCH indicating therelease of downlink SPS, with high efficiency.

An downlink assignment index (DAI) will be described below.

The DAI is used for detecting a PDCCH/EPDCCH for assigning PDSCHtransmission in which data transmitted from the base station apparatus 1is lost in the middle of transmission, and for detecting a PDCCH/EPDCCHfor performing an instruction of downlink SPS resource.

For example, in a situation in which plural pieces of HARQ responseinformation in a plurality of downlink subframes is transmitted in oneuplink subframe by HARQ response information bundling, even when aPDCCH/EPDCCH transmitted in a certain downlink subframe is lost, anddetection of the PDCCH/EPDCCH by the terminal device 2 is not possible,the terminal device 2 responds to ACK in a case where reception of thePDSCH of which an instruction is performed by a PDCCH/EPDCCH transmittedin another downlink subframe. Thus, the base station apparatus 1 doesnot enable detection of the lost PDCCH/EPDCCH.

Thus, the base station apparatus 1 notifies the terminal device 2 of avalue which is included in a DCI format, by using the DAI. The value ofwhich the notification is performed is based on the number of times oftransmitting a PDCCH/EPDCCH for performing an instruction of the releaseof downlink SPS, and based on the number of times of transmitting aPDCCH/EPDCCH among a plurality of downlink subframes corresponding toone uplink subframe in which HARQ response information can betransmitted in response to PDSCH transmission in the plurality ofdownlink subframes. The terminal device 2 acquires a value by using theDAI. The acquired value is based on the number of times of transmittinga PDCCH/EPDCCH for assigning PDSCH transmission, which has beentransmitted by the base station apparatus 1, and based on the number oftimes of transmitting a PDCCH/EPDCCH for performing an instruction ofthe release of downlink SPS. The terminal device 2 compares the acquiredvalue based on the number of times of transmitting the PDCCH/EPDCCH, tothe actual reception success number of the PDCCH/EPDCCH. If the value ofthe number of times of transmission is different from the receptionsuccess number, the terminal device 2 determines that the PDCCH/EPDCCHtransmitted in a certain downlink subframe is lost, and responds to thebase station apparatus 1 with NACK. Since the base station apparatus 1receives NACK, the base station apparatus 1 performs retransmissionprocessing in a state where a PDSCH corresponding to the lostPDCCH/EPDCCH is included. Thus, even when the PDCCH/EPDCCH is lost inthe middle of transmission, detection on the terminal device 2 side ispossible, and retransmission processing can be performed.

When HARQ response information is transmitted in a state of beingmultiplexed, the DAI is used for determining the number of bits of themultiplexed HARQ response information. The DAI is used for determiningthe number of bits of the HARQ response information which is transmittedon the PUCCH/PUSCH.

The DAI of which notification is performed in a state of being includedin the downlink grant indicates an accumulated value of PDCCH/EPDCCHsfor assigning PDSCH transmission and PDCCH/EPDCCHs for performing aninstruction of the release of downlink SPS until the current subframeamong a plurality of downlink subframes corresponding to one uplinksubframe in which HARQ response information can be transmitted inresponse to the PDSCH transmission in a plurality of downlink subframes.In other words, the DAI included in the downlink grant for triggeringPDSCH transmission in a subframe (n−k_(i)) indicates the number ofsubframes in which PDSCH transmission toward the terminal device 2 isperformed among subframes (from n−k₀ to n−k_(i-1)) ahead of the subframe(n−k_(i)) in a bundling window corresponding to the subframe n. ThePDSCH transmission includes PDSCH transmission by dynamic schedulingand/or PDSCH transmission by semi-persistent scheduling. In a case wherea DAI field has two bits, replacement with the actual number ofsubframes may be performed, and the remainder with respect to 4 of thenumber of subframes may be indicated.

The DAI of which notification is performed in a state of being includedin an uplink grant indicates the value of a PDCCH/EPDCCH for assigningtransmission of all PDSCHs and the value of a PDCCH/EPDCCH forperforming an instruction of the release of downlink SPS among aplurality of downlink subframes corresponding to one uplink subframe inwhich HARQ response information can be transmitted in response to thePDSCH transmission in a plurality of downlink subframes. In other words,the DAI included in the uplink grant for triggering PUSCH transmissionin the subframe n indicates the number of subframes in which PDSCHtransmission toward the terminal device 2 is performed in a bundlingwindow corresponding to the subframe n.

In the carrier aggregation between an FDD cell and a TDD cell, arelationship between a plurality of downlink subframes corresponding toone uplink subframe in which HARQ response information can betransmitted in response to the PDSCH transmission will be described.FIG. 8 illustrates an example 800 of the relationship between an uplinksubframe and a downlink subframe in transmission of HARQ responseinformation in response to the PDSCH transmission. In FIG. 8, it isassumed that Serving cell 1 is a TDD cell and Serving cell 2 is an FDDcell. HARQ response information in response to the PDSCH transmissionwhich has been transmitted in a downlink subframe of the subframe 1 istransmitted in an uplink subframe of Serving cell 1, and HARQ responseinformation in response to the PDSCH transmission which has beentransmitted in a downlink subframe of Serving cell 2 is also transmittedin the uplink subframe of Serving cell 1. In the example of FIG. 8, HARQresponse information in response to PDSCH transmission of the subframes0 and 1 (810) of Serving cell 1 is transmitted by using an uplinksubframe of the subframe 7 (820) of Serving cell 1. Since a plurality ofdownlink subframes is associated with one uplink subframe, detection oflosing the PDCCH/EPDCCH is performed by using information of the DAI.HARQ response information in response to PDSCH transmission of thesubframes 0, 1, 2, and 3 (830) of Serving cell 2 is also transmitted byusing the uplink subframe of the subframe 7 (820) of Serving cell 1. Inthis case, a plurality of downlink subframes (830) is also associatedwith one uplink subframe 820. That is, the information of the DAI isalso included in a PDCCH/EPDCCH indicating PDSCH transmission in an FDDcell, and thus losing the PDCCH/EPDCCH can be detected, andcommunication with high efficiency can be performed. As disclosed above,each of elements 810 and 830 may be referred to as a bundling window.

The DAI is configured for each terminal.

The DAI is commonly configured between cells which have been subjectedto carrier aggregation. The DAI may be configured for each of the cellswhich have been subjected to carrier aggregation. A case where the DAIis configured for each of the cells which have been subjected to carrieraggregation corresponds to, for example, a case where transmission of aPUCCH in the secondary cell is allowable.

In the following descriptions, the presence of the field of the DAI andapplication of the DAI assuming a case where a plurality of cells towhich different frame structure types are applied are aggregated will bedescribed.

Setting of the DAI is switched in accordance with the frame constitutiontype of a cell in which the HARQ response information is transmitted.For example, in a case where HARQ response information in an FDD cell istransmitted as a response in a TDD cell, a DAI field is set in the DCItransmitted in the FDD cell. In a case where HARQ response informationin a TDD cell is transmitted as a response in an FDD cell, a DAI fieldmay not be set in the DCI transmitted in the TDD cell.

Further, setting of the DAI may be switched in accordance with thetransmission timing of HARQ response information. For example, in a casewhere HARQ response information of an FDD cell is transmitted as aresponse in a TDD cell by using the transmission timing of HARQ responseinformation in the TDD cell, the HARQ response information istransmitted as a response for plurality of downlink subframes in oneuplink subframe. Thus, the DAI field is set. In a case where HARQresponse information of a TDD cell is transmitted as a response in anFDD cell by using the transmission timing of HARQ response informationin the FDD cell, the HARQ response information corresponding to onedownlink subframe is transmitted as a response in one uplink subframe.Thus, the DAI field is not set. In a case where HARQ responseinformation of a TDD cell is transmitted as a response in an FDD cell byusing the transmission timing of HARQ response information in the TDDcell, the HARQ response information corresponding to a plurality ofdownlink subframes is transmitted as a response in one uplink subframe.Thus, the DAI field is set. In addition, in a case where thetransmission timing of the HARQ response information of the TDD cell isalso applied to the FDD cell, if the HARQ response information of theFDD cell is transmitted as a response in the FDD cell, the DAI field isset in the DCI.

That is, in a case where the HARQ response information of the FDD cellis transmitted as a response in the TDD cell by using the transmissiontiming of the HARQ response information of the TDD cell, the DAI fieldis set in the DCI. In a case where the HARQ response information of theTDD cell is transmitted as a response in the FDD cell by using thetransmission timing of the HARQ response information of the TDD cell,the DAI field is set in the DCI. In a case where the HARQ responseinformation of the FDD cell is transmitted as a response in the FDD cellby using the transmission timing of the HARQ response information of theTDD cell, the DAI field is set in the DCI. In a case where the HARQresponse information of the TDD cell is transmitted as a response in theFDD cell by using the transmission timing of the HARQ responseinformation of the FDD cell, the DAI field may not be set in the DCI.

The base station apparatus 1 performs transmission on a PDCCH by using afirst DCI format or a second DCI format. The terminal device 2 performsreception on the PDCCH which has been transmitted by using the first DCIformat or the second DCI format. In a case where the total number ofcells of FDD and cells of TDD is set in the terminal device 2, a firstDAI indicates the accumulated number of PDCCHs or EPDCCHs indicatingPDSCH transmission or the release of downlink semi-persistent schedulingin subframes until now in a predetermined subframe. The first DAI isprovided in the first DCI format in the FDD cell, is applied to the FDDcell. A second DAI is provided in the second DCI format in the FDD cell,and is applied to the FDD cell.

An example of the presence of the field of the DAI and the applicationof the DAI by combining the primary cell and the secondary cell will bedescribed below.

An example of the presence of the field of the DAI included in the DCIrelating to a downlink grant will be described.

In a case where a PDSCH is transmitted in a TDD cell, the DAI isincluded in the DCI relating to the downlink grant, and is transmitted.In addition, in a case where a TDD cell is configured so as to be theprimary cell, and the PDSCH is transmitted in an FDD cell, the DAI isalso included in the DCI relating to the downlink grant, and istransmitted.

That is, a 2-bit field of the DAI is provided in the DCI transmitted byDCI format 1/1B/1D/2/2A/2B/2C/2D or DCI format 1A used for compactscheduling of a code word for one PDSCH in a certain cell, and a randomaccess procedure which is initialized by a PDCCH order, for TDD cells byall UL-DL configurations or for FDD secondary cells (FDD cellsaggregated in the TDD primary cell) in which the primary cell isoperated by TDD.

That is, the field of the DAI is not provided in the DCI transmitted byDCI format 1/1B/1D/2/2A/2B/2C/2D or DCI format 1A used for compactscheduling of a code word for one PDSCH in a certain cell, and a randomaccess procedure which is initialized by a PDCCH order, for FDD cells(FDD cells which are not aggregated in the TDD primary cell) in whichthe primary cell is not operated by TDD. In other words, the field ofthe DAI is not provided in the DCI transmitted in the FDD cell for theterminal device 2, in which the primary cell is configured by FDD.

An example of the presence of the field of the DAI included in the DCIrelating to a downlink grant will be described.

For example, in the terminal device 2 in which the FDD primary cell andthe TDD secondary cell are configured, the number of downlink subframesof the TDD secondary cell is smaller than the number of uplink subframesof the FDD primary cell. Thus, the value of the DAI is generally setto 1. In such a situation, since the information of the DAI is notrequired, the information of the DAI may be excluded from the DCI forcontrolling PDSCH scheduling of TDD cells. That is, in a case where theprimary cell is an FDD cell, the DAI field is not configured in a TDDcell and an FDD cell.

At a time of the TDD primary cell, in a case where a PDSCH istransmitted in the TDD cell, and in a case where a PDSCH is transmittedin the FDD cell, the DAI is also included in the DCI relating to thedownlink grant, and is transmitted. At a time of the FDD primary cell,in both of a case where a PDSCH is transmitted in the TDD cell, and acase where a PDSCH is transmitted in the FDD cell, the DAI istransmitted without being included in the DCI relating to the downlinkgrant.

That is, only when the primary cell is a TDD cell, a 2-bit field of theDAI is provided for a serving cell (FDD cell or TDD cell) in the DCItransmitted by DCI format 1/1B/1D/2/2A/2B/2C/2D or DCI format 1A usedfor compact scheduling of a code word for one PDSCH in a certain cell,and a random access procedure which is initialized by a PDCCH order.When the primary cell is an FDD cell, the field of the DAI is notprovided in the DCI.

An example of the presence of the field of the DAI included in the DCIrelating to a downlink grant will be described.

The DAI being required to be assigned in the FDD cell corresponds to acase where carrier aggregation between a TDD cell and an FDD cell isperformed, and the primary cell is a TDD cell. At this time, the DAIfield is assigned in the DCI for the FDD secondary cell. That is, onlyan USS is configured in the secondary cell. The presence of the field ofthe DAI is determined depending on the USS in which a PDCCH/EPDCCH forperforming an instruction of scheduling of an FDD cell is allocated.

That is, the field of the DAI is provided in the DCI transmitted by DCIformat 1/1B/1D/2/2A/2B/2C/2D or DCI format 1A used for compactscheduling of a code word for one PDSCH in a certain cell, and a randomaccess procedure which is initialized by a PDCCH order. The DCI isassigned in an USS for TDD cells by all UL-DL configurations or an FDDcell in which a TDD-FDD-CA configuration is configured in a higherlayer.

An example in which the DAI is included in a DCI format included in aPDCCH/EPDCCH which is transmitted in an USS of an FDD cell in a casewhere TDD-FDD-CA configuration is configured in a higher layer isdescribed. However, in a case where the TDD-FDD-CA configuration isconfigured in a higher layer, the DAI may be included in a DCI formattransmitted in a CSS of the FDD cell, and be transmitted.

An example of the presence of the field of the DAI included in the DCIrelating to a downlink grant will be described.

A PUCCH including HARQ response information is mainly transmitted byusing PUCCH resources of an uplink subframe of the primary cell. Sincethe number of downlink subframes of the FDD secondary cell is more thanthe number of uplink subframes of the TDD primary cell, the informationof the DAI is also required in the DCI for performing an instruction ofan FDD cell. In a case where a PUCCH including HARQ response informationcan be transmitted in an uplink subframe of the FDD secondary cell, theinformation of the DAI is not required in the DCI for performing aninstruction of an FDD cell.

That is, a 2-bit field of the DAI is provided in the DCI transmitted byDCI format 1/1B/1D/2/2A/2B/2C/2D or DCI format 1A used for compactscheduling of a code word for one PDSCH in a certain cell, and a randomaccess procedure which is initialized by a PDCCH order, for TDD cells byall UL-DL configurations or for FDD secondary cells (FDD cellsaggregated in the TDD primary cell) in which configuring of a PUCCHbeing transmitted in the FDD secondary cell is not performed by thehigher layer, and the primary cell is operated by TDD.

That is, in a case where configuring of a PUCCH being transmitted in theFDD secondary cell is performed by the higher layer, the field of theDAI is not provided in the DCI transmitted to the FDD cell.

An example of the presence of the field of the DAI included in the DCIrelating to a downlink grant will be described.

A 2-bit field of the DAI is provided in the DCI transmitted by DCIformat 1/1B/1D/2/2A/2B/2C/2D or DCI format 1A used for compactscheduling of a code word for one PDSCH in a certain cell, and a randomaccess procedure which is initialized by a PDCCH order, for TDD cells inwhich configuring of a PUCCH being transmitted in the FDD secondary cellis performed by the higher layer, or for serving cells (FDD cells or TDDcells) in which configuring of a PUCCH being transmitted in the FDDsecondary cell is not performed by the higher layer, and the primarycell is a TDD cell.

The field of the DAI is not provided in the DCI transmitted to the FDDcell in which configuring of a PUCCH being transmitted in the secondarycell is performed by the higher layer, or to a serving cell in whichtransmission of a PUCCH in the secondary cell is not configured by thehigher layer, and the primary cell is not a TDD cell.

An example of the presence of the field of the DAI included in the DCIrelating to an uplink grant will be described.

When a PDSCH is transmitted in a TDD cell in which the UL-DLconfiguration is configured so as to be (1-6), the DAI is transmittedwith being included in the DCI relating to an uplink grant. In a casewhere the TDD cell is configured as the primary cell, and a PDSCH istransmitted in an FDD cell, the DAI is also transmitted with beingincluded in the DCI relating to an uplink grant.

That is, a 2-bit field of the DAI is provided in the DCI transmitted byDCI format 0/4, for TDD cells in which the UL-DL configuration isconfigured so as to be (1-6), or for FDD secondary cells (FDD cellsaggregated in the TDD primary cell) in which the primary cell isoperated by TDD.

That is, the field of the DAI is not provided in the DCI transmitted byDCI format 0/4, for TDD cells in which the UL-DL configuration is notconfigured so as to be (1-6), or for FDD cells (FDD cells which are notaggregated in the TDD primary cell) in which the primary cell is notoperated by TDD.

An example of the presence of the field of the DAI included in the DCIrelating to an uplink grant will be described.

When the primary cell is a TDD cell, in a case where a PDSCH istransmitted in a TDD cell in which the UL-DL configuration is configuredso as to be (1-6), and in a case where a PDSCH is transmitted in an FDDcell, the DAI is also transmitted with being included in the DCIrelating to the uplink grant. When the primary cell is an FDD cell, in acase where a PDSCH is transmitted in a TDD cell, and in a case where aPDSCH is transmitted in an FDD cell, the DAI is also transmitted withoutbeing included in the DCI relating to the uplink grant.

That is, only when the primary cell is a TDD cell, a 2-bit field of theDAI is provided in the DCI transmitted by DCI format 0/4, for an FDDcell or a TDD cell in which the UL-DL configuration is configured so asto be (1-6).

That is, when the primary cell is not a TDD cell, the field of the DAIis not provided in the DCI transmitted by DCI format 0/4.

An example of the presence of the field of the DAI included in the DCIrelating to an uplink grant will be described.

Also in a case of the uplink grant, the presence of the field of the DAIis determined depending on a USS in which a PDCCH/EPDCCH for performingan instruction of scheduling of an FDD cell is allocated.

That is, a 2-bit field of the DAI is provided in the DCI transmitted toTDD cells in which the UL-DL configuration is configured so as to be(1-6), or is provided in the DCI transmitted by DCI format 0/4. The DCIis assigned in an USS of an FDD cell in which a TDD-FDD-CA configurationis configured in a higher layer.

An example in which the DAI is included in a DCI format included in aPDCCH/EPDCCH which is transmitted in an USS of an FDD cell in a casewhere TDD-FDD-CA configuration is configured in a higher layer isdescribed. However, in a case where the TDD-FDD-CA configuration isconfigured in a higher layer, the DAI may be included in a DCI formattransmitted in a CSS of the FDD cell, and be transmitted.

That is, the field of the DAI is not provided in the DCI transmitted byDCI format 0/4, for to a TDD cell in which the UL-DL configuration isset to be 0, or for an FDD cell in which the TDD-FDD-CA configuration isnot configured in a higher layer.

An example of the presence of the field of the DAI included in the DCIrelating to an uplink grant will be described.

In a case where configuring of a PUCCH being transmitted in the FDDsecondary cell is not performed by the higher layer, a 2-bit field ofthe DAI is provided in the DCI transmitted by DCI format 0/4, for FDDsecondary cells (FDD cell aggregated in the TDD primary cell) in whichthe primary cell is operated by TDD, or for TDD cells in which the UL-DLconfiguration is configured so as to be (1-6).

In a case where configuring of a PUCCH being transmitted in the FDDsecondary cell is performed by the higher layer, the field of the DAI isnot provided in the DCI transmitted by DCI format 0/4 for an FDD cell ora TDD cell in which the UL-DL configuration is configured so as to be 0.

An example of the presence of the field of the DAI included in the DCIrelating to an uplink grant will be described.

In a case where configuring of a PUCCH being transmitted in the FDDsecondary cell is performed by the higher layer, a 2-bit field of theDAI is provided in the DCI transmitted by DCI format 0/4, for TDD cellsin which the UL-DL configuration is configured so as to be (1-6).

In a case where configuring of a PUCCH being transmitted in the FDDsecondary cell is performed by the higher layer, the field of the DAI isnot provided in the DCI transmitted by DCI format 0/4, for TDD cells inwhich the UL-DL configuration is configured so as to be 0 and FDD cells.

An example of the application of the field of the DAI included in theDCI relating to a downlink grant will be described.

When carrier aggregation between a TDD cell and an FDD cell isperformed, the DAI field may be generally applied to an FDD cell.

In a case where one or more TDD cells are configured, and UL-DLconfigurations of all TDD cells are the same as each other, the field ofthe DAI in the DCI relating to the downlink grant is applied in a TDDcell in which the UL-DL configuration is configured so as to be (1-6).In addition, in a case where two or more TDD cells are configured, andat least two TDD cells are configured so as to have UL-DL configurationsdifferent from each other, the field of the DAI in the DCI relating tothe downlink grant is applied in a TDD cell in which the downlinkreference UL-DL configuration is configured so as to be (1-6). Inaddition, in a case where the primary cell is a TDD cell, and at leastone secondary cell is an FDD cell, the field of the DAI in the DCIrelating to the downlink grant is applied in an FDD cell.

That is, in a case where one TDD cell is configured in the terminaldevice 2, or in a case where TDD cells of which the number is more thanone are configured in the terminal device 2 and UD-DL configurations ofall TDD cells are the same as each other, the field of the DAI isapplied to a serving cell in which the UL-DL configuration is configuredso as to be (1-6). In a case where serving cells of which the number ismore than one are configured in the terminal device 2, and at least twoTDD cells have UL-DL configurations different from each other, or in acase where at least one serving cell is an FDD cell, the DAI field isapplied to an FDD cell or a TDD cell in which the downlink referenceUL-DL configuration is configured so as to be (1-6).

An example of the application of the field of the DAI included in theDCI relating to a downlink grant will be described.

The downlink reference UL-DL configuration is mainly configured in a TDDcell. When carrier aggregation between a TDD cell and an FDD cell isperformed, the downlink reference UL-DL configuration may be applied toan FDD cell. At this time, the DAI field is applied in accordance withthe downlink reference UL-DL configuration.

In a case where one or more TDD cells are configured in the terminaldevice 2, and UL-DL configurations of all TDD cells are the same as eachother, the field of the DAI in the DCI relating to the downlink grant isapplied to a TDD cell in which the UL-DL configuration is configured soas to be (1-6). In addition, in a case where two or more TDD cells areconfigured, and at least two TDD cells are configured so as to haveUL-DL configurations different from each other, the field of the DAI inthe DCI relating to the downlink grant is applied to a TDD cell in whichthe downlink reference UL-DL configuration is configured so as to be(1-6). In addition, in a case where the primary cell is a TDD cell, andat least one secondary cell is an FDD cell, the field of the DAI in theDCI relating to the downlink grant is applied to an FDD cell in whichthe downlink reference UL-DL configuration is configured so as to be(1-6).

That is, in a case where one serving cell is configured in the terminaldevice 2, or in a case where serving cells of which the number is morethan one are configured in the terminal device 2, and UD-DLconfigurations of all serving cells are the same as each other, thefield of the DAI is applied only to a serving cell in which the UL-DLconfiguration is configured so as to be (1-6). In a case where servingcells of which the number is more than one are configured in theterminal device 2, and at least two serving cells have UL-DLconfigurations different from each other, or in a case where at leastone serving cell is an FDD cell, the DAI field is applied to a servingcell (FDD cell, TDD cell) in which the downlink reference UL-DLconfiguration is configured so as to be (1-6).

An example of the application of the field of the DAI included in theDCI relating to an uplink grant will be described.

In a case where one or more TDD cells are configured, and UL-DLconfigurations of all TDD cells are the same as each other, the field ofthe DAI in the DCI relating to an uplink grant is applied in a TDD cellin which the UL-DL configuration is configured so as to be (1-6). Inaddition, in a case where two or more TDD cells are configured, and atleast two TDD cells are configured so as to have UL-DL configurationsdifferent from each other, the field of the DAI in the DCI relating tothe uplink grant is applied to a TDD cell in which the uplink referenceUL-DL configuration is configured so as to be (1-6). In addition, in acase where the primary cell is a TDD cell, and at least one secondarycell is an FDD cell, the field of the DAI in the DCI relating to theuplink grant is applied to an FDD cell.

That is, in a case where one TDD cell is configured in the terminaldevice 2, or in a case where TDD cells of which the number is more thanone are configured in the terminal device 2 and UD-DL configurations ofall TDD cells are the same as each other, the field of the DAI isapplied to a serving cell in which the UL-DL configuration is configuredso as to be (1-6). In a case where serving cells of which the number ismore than one are configured in the terminal device 2, and at least twoTDD cells have UL-DL configurations different from each other, or in acase where at least one serving cell is an FDD cell, the DAI field isapplied to an FDD cell or a TDD cell in which the uplink reference UL-DLconfiguration is configured so as to be (1-6).

An example of the application of the field of the DAI included in theDCI relating to an uplink grant will be described.

In a case where one or more TDD cells are configured in the terminaldevice 2, and UL-DL configurations of all TDD cells are the same as eachother, the field of the DAI in the DCI relating to the uplink grant isapplied to a TDD cell in which the UL-DL configuration is configured soas to be (1-6). In addition, in a case where two or more TDD cells areconfigured, and at least two TDD cells are configured so as to haveUL-DL configurations different from each other, the field of the DAI inthe DCI relating to the uplink grant is applied in a TDD cell in whichthe uplink reference UL-DL configuration is configured so as to be(1-6). In addition, in a case where the primary cell is a TDD cell, andat least one secondary cell is an FDD cell, the field of the DAI in theDCI relating to the uplink grant is applied in an FDD cell in which theuplink reference UL-DL configuration is configured so as to be (1-6).

That is, in a case where one TDD cell is configured in the terminaldevice 2, or in a case where TDD cells of which the number is more thanone are configured in the terminal device 2 and UD-DL configurations ofall TDD cells are the same as each other, the field of the DAI isapplied to a serving cell in which the UL-DL configuration is configuredso as to be (1-6). In a case where serving cells of which the number ismore than one are configured in the terminal device 2, and at least twoTDD cells have UL-DL configurations different from each other, or in acase where at least one serving cell is an FDD cell, the DAI field isapplied to an FDD cell or a TDD cell in which the uplink reference UL-DLconfiguration is configured so as to be (1-6).

A combination of the presence of the field of the DAI included in theDCI relating to the downlink grant or the uplink grant, and theapplication of the DAI is not limited. However, an example of apreferable combination thereof will be described below.

An example of a combination of the presence of the field of the DAIincluded in the DCI relating to the downlink grant or the uplink grant,and the application of the DAI will be described.

In a case where one TDD cell is configured in the terminal device 2, orin a case where serving cells of which the number is more than one areconfigured in the terminal device 2, and the primary cell is a TDD cell,the base station apparatus 1 configures the DAI field in the DCIincluded in a PDCCH/EPDCCH which is transmitted in association with aTDD cell and an FDD cell.

A 2-bit field of the DAI is provided in the DCI transmitted by DCIformat 1/1B/1D/2/2A/2B/2C/2D or DCI format 1A used for compactscheduling of a code word for one PDSCH in a certain cell, and a randomaccess procedure which is initialized by a PDCCH order, for TDD cells byall UL-DL configurations or for FDD secondary cells (FDD cellsaggregated in the TDD primary cell) in which the primary cell isoperated by TDD.

Thus, in a case where one TDD cell is configured in the terminal device2, or in a case where TDD cells of which the number is more than one areconfigured in the terminal device 2, and UD-DL configurations of all TDDcells are the same as each other, the field of the DAI is applied to aserving cell in which the UL-DL configuration is configured so as to be(1-6). In a case where serving cells of which the number is more thanone are configured in the terminal device 2, and at least two TDD cellshave UL-DL configurations different from each other, or in a case whereat least one serving cell is an FDD cell, the DAI field is applied to anFDD cell or a TDD cell in which the downlink reference UL-DLconfiguration is configured so as to be (1-6). In other words, in a casewhere one TDD cell is configured in the terminal device 2, or in a casewhere serving cells of which the number is more than one are configuredin the terminal device 2, and UD-DL configurations of all serving cellsare the same as each other, the field of the DAI is not applied to aserving cell in which the UL-DL configuration is configured so as to be0. In a case where serving cells of which the number is more than oneare configured in the terminal device 2, and at least two serving cellshave UL-DL configurations different from each other, the DAI field isnot applied to a serving cell in which the downlink reference UL-DLconfiguration is configured so as to be 0.

The field of the DAI is not provided in the DCI transmitted to FDD cells(FDD cells which are not aggregated in the TDD primary cell) in whichthe primary cell is not operated by TDD. In other words, the field ofthe DAI is not provided in the DCI transmitted in an FDD cell to theterminal device 2 in which the primary cell is configured by FDD.

A 2-bit field of the DAI is provided for a TDD cell in the DCItransmitted by DCI format 1A in which CRC is scrambled by the RA-RNTI,the P-RNTI, or the SI-RNTI.

The field of the DAI is not provided for an FDD cell in the DCItransmitted by DCI format 1A in which CRC is scrambled by the RA-RNTI,the P-RNTI, or the SI-RNTI.

A 2-bit field of the DAI is provided in the DCI transmitted by DCIformat 0/4, for TDD cells in which the UL-DL configuration is configuredso as to be (1-6), or for FDD secondary cells (FDD cells aggregated inthe TDD primary cell) in which the primary cell is operated by TDD.

In a case where one TDD cell is configured in the terminal device 2, orin a case where TDD cells of which the number is more than one areconfigured in the terminal device 2 and UD-DL configurations of all TDDcells are the same as each other, the field of the DAI is applied to aserving cell in which the UL-DL configuration is configured so as to be(1-6). In a case where serving cells of which the number is more thanone are configured in the terminal device 2, and at least two TDD cellshave UL-DL configurations different from each other, or in a case whereat least one serving cell is an FDD cell, the DAI field is applied to anFDD cell or a TDD cell in which the uplink reference UL-DL configurationis configured so as to be (1-6).

The field of the DAI is not provided in the DCI transmitted by DCIformat 0/4, for TDD cells in which the UL-DL configuration is notconfigured so as to be (1-6), or for FDD cells (FDD cells which are notaggregated in the TDD primary cell) in which the primary cell is notoperated by TDD. In other words, the field of the DAI is not provided inthe DCI transmitted by DCI format 0/4, for a TDD cell in which the UL-DLconfiguration is configured so as to be 0, or for an FDD cell in whichthe primary cell is operated by FDD.

An example of a combination of the presence of the field of the DAIincluded in the DCI relating to the downlink grant or the uplink grant,and the application of the DAI will be described.

In a case where one TDD cell is configured in the terminal device 2, orin a case where serving cells of which the number is more than one areconfigured in the terminal device 2, and the primary cell is a TDD cell,the base station apparatus 1 configures the DAI field in the DCIincluded in a PDCCH/EPDCCH which is transmitted in association with aserving cell (TDD cell, FDD cell).

Only when the primary cell is a TDD cell, a 2-bit field of the DAI isprovided in the DCI transmitted by DCI format 1/1B/1D/2/2A/2B/2C/2D orDCI format 1A used for compact scheduling of a code word for one PDSCHin a certain cell, and a random access procedure which is initialized bya PDCCH order, for serving cells (FDD cells or TDD cells). When theprimary cell is an FDD cell, the field of the DAI is not provided in theDCI.

Regardless of whether or not the primary cell is a TDD cell, a 2-bitfield may be reserved in the DCI transmitted by DCI format1/1B/1D/2/2A/2B/2C/2D or DCI format 1A used for compact scheduling of acode word for one PDSCH in a certain cell, and a random access procedurewhich is initialized by a PDCCH order, for TDD cells in which the UL-DLconfiguration is configured so as to be 0.

In a case where one serving cell is configured in the terminal device 2,or in a case where serving cells of which the number is more than oneare configured in the terminal device 2, and UD-DL configurations of allserving cells are the same as each other, the field of the DAI isapplied to a serving cell in which the UL-DL configuration is configuredso as to be (1-6). In a case where serving cells of which the number ismore than one are configured in the terminal device 2, and at least twoserving cells have UL-DL configurations different from each other, or ina case where at least one serving cell is an FDD cell, the DAI field isapplied to an FDD cell or a TDD cell in which the downlink referenceUL-DL configuration is configured so as to be (1-6). In other words, ina case where one serving cell is configured in the terminal device 2, orin a case where serving cells of which the number is more than one areconfigured in the terminal device 2, and UD-DL configurations of allserving cells are the same as each other, the field of the DAI is notapplied to a serving cell in which the UL-DL configuration is configuredso as to be 0. In a case where serving cells of which the number is morethan one are configured in the terminal device 2, and at least twoserving cells have UL-DL configurations different from each other, or ina case where at least one serving cell is an FDD cell, the DAI field isnot applied to a serving cell in which the downlink reference UL-DLconfiguration is configured so as to be 0.

A 2-bit field of the DAI is provided for a TDD cell in the DCItransmitted by DCI format 1A in which CRC is scrambled by the RA-RNTI,the P-RNTI, or the SI-RNTI.

The field of the DAI is not provided for an FDD cell in the DCItransmitted by DCI format 1A in which CRC is scrambled by the RA-RNTI,the P-RNTI, or the SI-RNTI.

Only when the primary cell is a TDD cell, a 2-bit field of the DAI isprovided in the DCI transmitted by DCI format 0/4, for an FDD cell or aTDD cell in which the UL-DL configuration is not configured so as to be(1-6). When the primary cell is not a TDD cell, the field of the DAI isnot provided in the DCI transmitted by DCI format 0/4.

Thus, in a case where one TDD cell is configured in the terminal device2, or in a case where TDD cells of which the number is more than one areconfigured in the terminal device 2, and UD-DL configurations of all TDDcells are the same as each other, the field of the DAI is applied to aserving cell in which the UL-DL configuration is configured so as to be(1-6). In a case where serving cells of which the number is more thanone are configured in the terminal device 2, and at least two TDD cellshave UL-DL configurations different from each other, or in a case whereat least one serving cell is an FDD cell, the DAI field is applied to anFDD cell or a TDD cell in which the uplink reference UL-DL configurationis configured so as to be (1-6).

The field of the DAI may not be reserved in the DCI transmitted by DCIformat 0/4, for TDD cells in which the UL-DL configuration is configuredso as to be 0.

An example of a combination of the presence of the field of the DAIincluded in the DCI relating to the downlink grant or the uplink grant,and the application of the DAI will be described.

In a case where one TDD cell is configured in the terminal device 2, ina case where serving cells of which the number is more than one areconfigured in the terminal device 2, in a case where all serving cellsare TDD cells, or in a case where serving cells of which the number ismore than one are configured in the terminal device 2 and at least onethereof is configured as the FDD secondary cell, the base stationapparatus 1 configures the DAI field in the DCI included in aPDCCH/EPDCCH which is transmitted in association with the TDD cell andthe FDD cell. A timing (subframe) at which HARQ response informationcorresponding to the PDCCH/EPDCCH which is associated with the FDD cellis transmitted in the terminal device 2 is determined in accordance withthe downlink reference UL-DL configuration.

The field of the DAI is provided in the DCI transmitted by DCI format1/1B/1D/2/2A/2B/2C/2D or DCI format 1A used for compact scheduling of acode word for one PDSCH in a certain cell, and a random access procedurewhich is initialized by a PDCCH order, for TDD cells by all UL-DLconfigurations or for FDD secondary cells (FDD cells aggregated in theTDD primary cell) in which the primary cell is operated by TDD.

Thus, in a case where one serving cell is configured in the terminaldevice 2, or in a case where serving cells of which the number is morethan one are configured in the terminal device 2, and UD-DLconfigurations of all serving cells are the same as each other, thefield of the DAI is applied only to a serving cell in which the UL-DLconfiguration is configured so as to be (1-6). In a case where servingcells of which the number is more than one are configured in theterminal device 2, and at least two serving cells have UL-DLconfigurations different from each other, or in a case where at leastone serving cell is an FDD cell, the DAI field is applied to a servingcell in which the downlink reference UL-DL configuration is configuredso as to be (1-6). In other words, in a case where one serving cell isconfigured in the terminal device 2, or in a case where serving cells ofwhich the number is more than one are configured in the terminal device2, and UD-DL configurations of all serving cells are the same as eachother, the field of the DAI is not applied to a serving cell in whichthe UL-DL configuration is configured so as to be 0. In a case whereserving cells of which the number is more than one are configured in theterminal device 2, and at least two serving cells have UL-DLconfigurations different from each other, the DAI field is not appliedto a serving cell in which the downlink reference UL-DL configuration isconfigured so as to be 0.

The field of the DAI is not provided in the DCI transmitted to FDD cells(FDD cells which are not aggregated in the TDD primary cell) in whichthe primary cell is not operated by TDD. In other words, the field ofthe DAI is not provided in the DCI transmitted to the terminal device 2in which the primary cell is configured by FDD.

A 2-bit field of the DAI is provided for a TDD cell in the DCItransmitted by DCI format 1A in which CRC is scrambled by the RA-RNTI,the P-RNTI, or the SI-RNTI.

The field of the DAI is not provided for an FDD cell in the DCItransmitted by DCI format 1A in which CRC is scrambled by the RA-RNTI,the P-RNTI, or the SI-RNTI.

The 2-bit field of the DAI is provided in the DCI transmitted by DCIformat 0/4, for TDD cells in which the UL-DL configuration is configuredso as to be (1-6), or for FDD secondary cells (FDD cells aggregated inthe TDD primary cell) in which the primary cell is operated by TDD.

In a case where one TDD cell is configured in the terminal device 2, orin a case where TDD cells of which the number is more than one areconfigured in the terminal device 2 and UD-DL configurations of all TDDcells are the same as each other, the field of the DAI is applied to aserving cell in which the UL-DL configuration is configured so as to be(1-6). In a case where serving cells of which the number is more thanone are configured in the terminal device 2, and at least two TDD cellshave UL-DL configurations different from each other, or in a case whereat least one serving cell is an FDD cell, the DAI field is applied to aserving cell in which the uplink reference UL-DL configuration isconfigured so as to be (1-6).

The field of the DAI is not provided in the DCI transmitted by DCIformat 0/4, for TDD cells in which the UL-DL configuration is configuredso as to be 0, or for FDD cells (FDD cells which are not aggregated inthe TDD primary cell) in which the primary cell is not operated by TDD.

An example of a combination of the presence of the field of the DAIincluded in the DCI relating to the downlink grant or the uplink grant,and the application of the DAI will be described.

In a case where one TDD cell is configured in the terminal device 2, orin a case where serving cells of which the number is more than one areconfigured in the terminal device 2, and the primary cell is a TDD cell,the base station apparatus 1 configures the DAI field in the DCIincluded in a PDCCH/EPDCCH which is transmitted in association with aTDD cell and an FDD cell. A timing (subframe) at which HARQ responseinformation corresponding to the PDCCH/EPDCCH which is associated withthe FDD cell is transmitted in the terminal device 2 is determined inaccordance with the downlink reference UL-DL configuration.

Only when the primary cell is a TDD cell, the field of the DAI isprovided in the DCI transmitted by DCI format 1/1B/1D/2/2A/2B/2C/2D orDCI format 1A used for compact scheduling of a code word for one PDSCHin a certain cell, and a random access procedure which is initialized bya PDCCH order. When the primary cell is not a TDD cell, the field of theDAI is not provided in the DCI.

The 2-bit field may be reserved in the DCI transmitted by DCI format1/1B/1D/2/2A/2B/2C/2D or DCI format 1A used for compact scheduling of acode word for one PDSCH in a certain cell, and a random access procedurewhich is initialized by a PDCCH order, for TDD cells in which the UL-DLconfiguration is configured so as to be 0.

In a case where one serving cell is configured in the terminal device 2,or in a case where serving cells of which the number is more than oneare configured in the terminal device 2, and UD-DL configurations of allserving cells are the same as each other, the field of the DAI isapplied to a serving cell in which the UL-DL configuration is configuredso as to be (1-6). In a case where serving cells of which the number ismore than one are configured in the terminal device 2, and at least twoserving cells have UL-DL configurations different from each other, or ina case where at least one serving cell is an FDD cell, the DAI field isapplied to a serving cell in which the downlink reference UL-DLconfiguration is configured so as to be (1-6). In other words, in a casewhere one serving cell is configured in the terminal device 2, or in acase where serving cells of which the number is more than one areconfigured in the terminal device 2, and UD-DL configurations of allserving cells are the same as each other, the field of the DAI is notapplied to a serving cell in which the UL-DL configuration is configuredso as to be 0. In a case where serving cells of which the number is morethan one are configured in the terminal device 2, and at least twoserving cells have UL-DL configurations different from each other, or ina case where at least one serving cell is an FDD cell, the DAI field isnot applied to a serving cell in which the downlink reference UL-DLconfiguration is configured so as to be 0.

The 2-bit field of the DAI is provided for a TDD cell in the DCItransmitted by DCI format 1A in which CRC is scrambled by the RA-RNTI,the P-RNTI, or the SI-RNTI.

The field of the DAI is not provided for an FDD cell in the DCItransmitted by DCI format 1A in which CRC is scrambled by the RA-RNTI,the P-RNTI, or the SI-RNTI.

Only when the primary cell is a TDD cell, the 2-bit field of the DAI isprovided for a serving cell in the DCI transmitted by DCI format 0/4.When the primary cell is not a TDD cell, the field of the DAI is notprovided in the DCI transmitted by DCI format 0/4.

In a case where one TDD cell is configured in the terminal device 2, orin a case where TDD cells of which the number is more than one areconfigured in the terminal device 2, and UD-DL configurations of all TDDcells are the same as each other, the field of the DAI is applied to aserving cell in which the UL-DL configuration is configured so as to be(1-6). In a case where serving cells of which the number is more thanone are configured in the terminal device 2, and at least two TDD cellshave UL-DL configurations different from each other, or in a case whereat least one serving cell is an FDD cell, the DAI field is applied to aserving cell in which the uplink reference UL-DL configuration isconfigured so as to be (1-6).

An example of a combination of the presence of the field of the DAIincluded in the DCI relating to the downlink grant or the uplink grant,and the application of the DAI will be described.

In a case where one TDD cell is configured in the terminal device 2, andin a case where serving cells of which the number is more than one areconfigured in the terminal device 2, and all serving cells are TDDcells, the base station apparatus 1 configures the DAI field in the DCIincluded in a PDCCH/EPDCCH which is transmitted in association with theTDD cell. In a case where the TDD-FDD-CA configuration is configured inthe terminal device 2 by a higher layer, and at least one is configuredas an FDD cell, the base station apparatus 1 configures the DAI field inthe DCI included in a PDCCH/EPDCCH which is allocated and transmitted inan USS which is associated with the FDD cell.

The TDD-FDD-CA configuration is a configuration in which frameconstitution types of at least two serving cells are allowed to bedifferent from each other in the terminal device 2.

The field of the DAI is provided in the DCI transmitted by DCI format1/1B/1D/2/2A/2B/2C/2D or DCI format 1A used for compact scheduling of acode word for one PDSCH in a certain cell, and a random access procedurewhich is initialized by a PDCCH order. The DCI is assigned in an USS forTDD cells by all UL-DL configurations or an FDD cell in which aTDD-FDD-CA configuration is configured in a higher layer.

Thus, in a case where one serving cell is configured in the terminaldevice 2, or in a case where serving cells of which the number is morethan one are configured in the terminal device 2, and UD-DLconfigurations of all serving cells are the same as each other, thefield of the DAI is applied only to a serving cell in which the UL-DLconfiguration is configured so as to be (1-6). In a case where servingcells of which the number is more than one are configured in theterminal device 2, and at least two serving cells have UL-DLconfigurations different from each other, or in a case where at leastone secondary cell is an FDD cell, the DAI field is applied to an FDDcell or a TDD cell in which the downlink reference UL-DL configurationis configured so as to be (1-6). In other words, in a case where oneserving cell is configured in the terminal device 2, or in a case whereserving cells of which the number is more than one are configured in theterminal device 2, and UD-DL configurations of all serving cells are thesame as each other, the field of the DAI is not applied to a servingcell in which the UL-DL configuration is configured so as to be 0. In acase where serving cells of which the number is more than one areconfigured in the terminal device 2, and at least two serving cells haveUL-DL configurations different from each other, the DAI field is notapplied to a serving cell in which the downlink reference UL-DLconfiguration is configured so as to be 0.

Thus, the TDD-FDD-CA configuration is not configured in the higherlayer, and the field of the DAI is not provided in the DCI transmittedto the FDD cell.

The 2-bit field of the DAI is provided for a TDD cell in the DCItransmitted by DCI format 1A in which CRC is scrambled by the RA-RNTI,the P-RNTI, or the SI-RNTI.

The field of the DAI is not provided for an FDD cell in the DCItransmitted by DCI format 1A in which CRC is scrambled by the RA-RNTI,the P-RNTI, or the SI-RNTI.

The 2-bit field of the DAI is provided for TDD cells in which the UL-DLconfiguration is configured so as to be (1-6) in the DCI or is providedin the DCI transmitted by DCI format 0/4, which is assigned in the USSof the FDD cell in which the TDD-FDD-CA configuration is configured inthe higher layer.

The field of the DAI is not provided in the DCI transmitted by DCIformat 0/4, for TDD cells in which the UL-DL configuration is configuredso as to be 0, or for FDD cells in which the TDD-FDD-CA configuration isnot configured in the higher layer.

An example of a combination of the presence of the field of the DAIincluded in the DCI relating to the downlink grant or the uplink grant,and the application of the DAI will be described.

In a case where the configuring of allowing the PUCCH to be transmittedin the secondary cell is not performed by the higher layer, and furtherin a case where one TDD cell is configured in the terminal device 2, orin a case where serving cells of which the number is more than one areconfigured in the terminal device 2, and the primary cell is a TDD cell,the base station apparatus 1 configures the DAI field in the DCIincluded in a PDCCH/EPDCCH which is transmitted in association with theTDD cell and the FDD cell. In other words, in a case where configuringof allowing the PUCCH to be transmitted in the secondary cell isperformed by the higher layer, the base station apparatus 1 does notconfigure the DAI field in the DCI included in a PDCCH/EPDCCH which istransmitted in association with the FDD cell.

The 2-bit field of the DAI is provided in the DCI transmitted by DCIformat 1/1B/1D/2/2A/2B/2C/2D or DCI format 1A used for compactscheduling of a code word for one PDSCH in a certain cell, and a randomaccess procedure which is initialized by a PDCCH order, for TDD cells byall UL-DL configurations or for FDD secondary cells (FDD cellsaggregated in the TDD primary cell) in which configuring of a PUCCHbeing transmitted in the FDD secondary cell is not performed by thehigher layer, and the primary cell is operated by TDD.

In a case where one TDD cell is configured in the terminal device 2, orin a case where TDD cells of which the number is more than one areconfigured in the terminal device 2 and UD-DL configurations of all TDDcells are the same as each other, the field of the DAI is applied to aserving cell in which the UL-DL configuration is configured so as to be(1-6). In a case where serving cells of which the number is more thanone are configured in the terminal device 2, and at least two TDD cellshave UL-DL configurations different from each other, or in a case whereat least one serving cell is an FDD cell, the DAI field is applied to anFDD cell or a TDD cell in which the downlink reference UL-DLconfiguration is configured so as to be (1-6). In other words, in a casewhere one TDD cell is configured in the terminal device 2, or in a casewhere serving cells of which the number is more than one are configuredin the terminal device 2, and UD-DL configurations of all serving cellsare the same as each other, the field of the DAI is not applied to aserving cell in which the UL-DL configuration is configured so as to be0. In a case where serving cells of which the number is more than oneare configured in the terminal device 2, and at least two serving cellshave UL-DL configurations different from each other, the DAI field isnot applied to a serving cell in which the downlink reference UL-DLconfiguration is configured so as to be 0.

In a case where configuring of a PUCCH being transmitted in the FDDsecondary cell is performed by the higher layer, the field of the DAI isnot provided in the DCI transmitted to the FDD cell.

The 2-bit field of the DAI is provided for a TDD cell in the DCItransmitted by DCI format 1A in which CRC is scrambled by the RA-RNTI,the P-RNTI, or the SI-RNTI.

The field of the DAI is not provided for an FDD cell in the DCItransmitted by DCI format 1A in which CRC is scrambled by the RA-RNTI,the P-RNTI, or the SI-RNTI.

In a case where configuring of a PUCCH being transmitted in the FDDsecondary cell is not performed by the higher layer, a 2-bit field ofthe DAI is provided in the DCI transmitted by DCI format 0/4, for FDDsecondary cells (FDD cell aggregated in the TDD primary cell) in whichthe primary cell is operated by TDD, or for TDD cells in which the UL-DLconfiguration is configured so as to be (1-6).

Thus, in a case where one TDD cell is configured in the terminal device2, or in a case where TDD cells of which the number is more than one areconfigured in the terminal device 2, and UD-DL configurations of all TDDcells are the same as each other, the field of the DAI is applied to aserving cell in which the UL-DL configuration is configured so as to be(1-6). In a case where serving cells of which the number is more thanone are configured in the terminal device 2, and at least two TDD cellshave UL-DL configurations different from each other, or in a case whereat least one serving cell is an FDD cell, the DAI field is applied to anFDD cell or a TDD cell in which the uplink reference UL-DL configurationis configured so as to be (1-6).

in a case where configuring of a PUCCH being transmitted in the FDDsecondary cell is performed by the higher layer, the field of the DAI isnot provided in the DCI transmitted by DCI format 0/4 for an FDD celland a TDD cell in which the UL-DL configuration is configured so as tobe 0.

An example of a combination of the presence of the field of the DAIincluded in the DCI relating to the downlink grant or the uplink grant,and the application of the DAI will be described.

In a case where a PUCCH including HARQ response information isconfigured so as to be allowed to be transmitted in the uplink subframeof the FDD secondary cell, and in a case where the PUCCH including theDAI for the TDD cell or the PUCCH including HARQ response information isnot configured so as to be allowed to be transmitted in the uplinksubframe of the FDD secondary cell, when the primary cell is a TDD cell,the PUCCH is transmitted with including the DAI for a serving cell (FDDcell, TDD cell).

That is, in a case where configuring of allowing the PUCCH to betransmitted in the secondary cell is not performed by the higher layer,in a case where one TDD cell is configured in the terminal device 2, orin a case where serving cells of which the number is more than one areconfigured in the terminal device 2, and the primary cell is a TDD cell,the base station apparatus 1 configures the DAI field in the DCIincluded in a PDCCH/EPDCCH which is transmitted in association with theserving cell (FDD cell, TDD cell).

The 2-bit field of the DAI is provided in the DCI transmitted by DCIformat 1/1B/1D/2/2A/2B/2C/2D or DCI format 1A used for compactscheduling of a code word for one PDSCH in a certain cell, and a randomaccess procedure which is initialized by a PDCCH order, for TDD cells inwhich configuring of a PUCCH being transmitted in the FDD secondary cellis performed by the higher layer, or for serving cells (FDD cells or TDDcells) in which configuring of a PUCCH being transmitted in the FDDsecondary cell is not performed by the higher layer, and the primarycell is a TDD cell.

In a case where one TDD cell is configured in the terminal device 2, orin a case where TDD cells of which the number is more than one areconfigured in the terminal device 2 and UD-DL configurations of all TDDcells are the same as each other, the field of the DAI is applied to aserving cell in which the UL-DL configuration is configured so as to be(1-6). In a case where serving cells of which the number is more thanone are configured in the terminal device 2, and at least two TDD cellshave UL-DL configurations different from each other, or in a case whereat least one serving cell is an FDD cell, the DAI field is applied to anFDD cell or a TDD cell in which the downlink reference UL-DLconfiguration is configured so as to be (1-6). In other words, in a casewhere one TDD cell is configured in the terminal device 2, or in a casewhere serving cells of which the number is more than one are configuredin the terminal device 2, and UD-DL configurations of all serving cellsare the same as each other, the field of the DAI is not applied to aserving cell in which the UL-DL configuration is configured so as to be0. In a case where serving cells of which the number is more than oneare configured in the terminal device 2, and at least two serving cellshave UL-DL configurations different from each other, the DAI field isnot applied to a serving cell in which the downlink reference UL-DLconfiguration is configured so as to be 0.

The field of the DAI is not provided in the DCI transmitted to the FDDcell in which configuring of a PUCCH being transmitted in the secondarycell is not performed by the higher layer, or to a serving cell in whichtransmission of a PUCCH in the secondary cell is not configured by thehigher layer, and the primary cell is not a TDD cell.

The 2-bit field of the DAI is provided for a TDD cell in the DCItransmitted by DCI format 1A in which CRC is scrambled by the RA-RNTI,the P-RNTI, or the SI-RNTI.

The field of the DAI is not provided for an FDD cell in the DCItransmitted by DCI format 1A in which CRC is scrambled by the RA-RNTI,the P-RNTI, or the SI-RNTI.

In a case where configuring of a PUCCH being transmitted in the FDDsecondary cell is performed by the higher layer, a 2-bit field of theDAI is provided in the DCI transmitted by DCI format 0/4, for TDD cellsin which the UL-DL configuration is configured so as to be (1-6).

In a case where one TDD cell is configured in the terminal device 2, orin a case where TDD cells of which the number is more than one areconfigured in the terminal device 2, and UD-DL configurations of all TDDcells are the same as each other, the field of the DAI is applied to aserving cell in which the UL-DL configuration is configured so as to be(1-6). In a case where serving cells of which the number is more thanone are configured in the terminal device 2, and at least two TDD cellshave UL-DL configurations different from each other, or in a case whereat least one serving cell is an FDD cell, the DAI field is applied to anFDD cell or a TDD cell in which the uplink reference UL-DL configurationis configured so as to be (1-6).

In a case where configuring of a PUCCH being transmitted in the FDDsecondary cell is performed by the higher layer, the field of the DAI isnot provided in the DCI transmitted by DCI format 0/4, for TDD cells inwhich the UL-DL configuration is configured so as to be 0 and FDD cells.

Thus, the terminal device 2 can perform efficient communication by usingthe DAI.

In a case where frame structure types (FDD (Type 1) and TDD (Type 2))which are different from each other are applied in the primary cell andat least one secondary cell, the terminal device 2 which performs cellaggregation (carrier aggregation) does not perform simultaneoustransmission and reception between the primary cell and the secondarycell as long as a function (performance, capacity) for performingsimultaneous transmission and reception between bands supported in theterminal device 2 by each of the primary cell and the secondary cell isnot provided.

The embodiment may be also applied for a different band (E-UTRAOperating Band, E-UTRA Band, Band).

Here, a band in which a duplex mode is TDD may be also referred to as aTDD band, and a band in which a duplex mode is FDD may be also referredto as an FDD band. Similarly, a cell (carrier) of which the framestructure type is FDD (Type 1) may be also referred to as an FDD cell(FDD carrier), and a cell (carrier) of which the frame structure type isTDD (Type 2) may be also referred to as a TDD cell (TDD carrier).

FIG. 1 is a schematic block diagram illustrating a configuration of thebase station apparatus 1 according to the present invention. Asillustrated in FIG. 1, the base station apparatus 1 includes a higherlayer processing unit 101, a control unit 103, a reception unit 105, atransmission unit 107, a channel measurement unit 109, and atransmit/receive antenna 111. The reception unit 105 includes a decodingportion 1051, a demodulation portion 1053, a demultiplexing portion1055, and a radio reception portion 1057. Reception processing of thebase station apparatus 1 is performed by the higher layer processingunit 101, the control unit 103, the reception unit 105, and thetransmit/receive antenna 111. The transmission unit 107 includes acoding portion 1071, a modulation portion 1073, a multiplexing portion1075, a radio transmission portion 1077, and a downlink reference signalgeneration portion 1079. Transmission processing of the base stationapparatus 1 is performed by the higher layer processing unit 101, thecontrol unit 103, the transmission unit 107, and the transmit/receiveantenna 111.

The higher layer processing unit 101 performs processing of a mediumaccess control (MAC) layer, a packet data convergence protocol (PDCP)layer, a radio link control (RLC) layer, and a radio resource control(RRC) layer.

The higher layer processing unit 101 generates information assigned ineach channel of a downlink, or acquires the information from a highernode, and then outputs the information to the transmission unit 107. Thehigher layer processing unit 101 assigns radio resources for causing theterminal device 2 to allocate a physical uplink shared channel (PUSCH)which is data information of an uplink, from radio resources of theuplink. The higher layer processing unit 101 determines radio resourcesfor allocating a physical downlink shared channel (PDSCH) which is datainformation of a downlink, from radio resources of the downlink.

The higher layer processing unit 101 generates downlink controlinformation indicating assignment of the radio resources, and transmitsthe generated information to the terminal device 2 through thetransmission unit 107.

The higher layer processing unit 101 preferentially allocates radioresources having good channel quality, based on a channel measurementresult of the uplink, which is input from the channel measurement unit109 when radio resources for allocating the PUSCH are assigned. That is,the higher layer processing unit 101 generates information regardingconfigurations of various downlink signals, and information regardingconfigurations of various uplink signals for a certain terminal deviceor a certain cell.

The higher layer processing unit 101 may generates information regardingsetting of various downlink signals, and information regarding settingof various uplink signals for each cell. The higher layer processingunit 101 may generates information regarding configurations of variousdownlink signals, and information regarding configurations of variousuplink signals for each terminal device 2.

The higher layer processing unit 101 may generate plural pieces ofinformation from information regarding a first configuration toinformation regarding an n-th configuration (n is natural number), andmay transmit the generated pieces of information to the terminal device2 through the transmission unit 107. The pieces of information aregenerated for a certain terminal device 2 or a certain cell, that is,are generated so as to be terminal device-specific or cell-specific. Forexample, the information regarding configurations of the downlink signaland/or the uplink signal may include parameters relating to resourceassignment.

The information regarding configurations of the downlink signal and/orthe uplink signal may include parameters used in calculating a sequence.The radio resources may be also referred to time-frequency resources,subcarriers, resource elements (RE), a resource element group (REG),control channel elements (CCE), a resource block (RB), a resource blockgroup (RBG), and the like.

Each of the configuration information and the control information may bedefined as an information element. Each of the configuration informationand the control information may be defined as an RRC message. Each ofthe configuration information and the control information may betransmitted as system information, to the terminal device 2. Theconfiguration information and the control information may be transmittedto the terminal device 2 by dedicated signaling.

The higher layer processing unit 101 configures at least one TDD UL/DLconfiguration (TDD UL/DL configuration(s), TDD config, tdd-Config, anduplink-downlink configuration(s)) in the system information blockType 1. The TDD UL/DL configuration may be defined as in a TDD UL/DLconfiguration table 300 of FIG. 3, where each of several UL/DLconfigurations 310 index a respective periodicity 312 and a particularassignment of special subframes 314, uplink subframes 316 and downlinksubframes 318 to specific subframe numbers 320. The constitution of TDDmay thus be shown by configuring an index (e.g., numbered 1-6 if FIG.3). A second TDD UL/DL configuration may be configured as a downlinkreference. The system information block may prepare a plurality oftypes. For example, the system information block Type 1 includes aninformation element regarding the TDD UL/DL configuration.

The system information block Type 2 includes an information elementregarding a radio resource control. A parameter relating to aninformation element thereof may be included as an information element incertain information elements. For example, referring to a parameter maybe performed in a physical layer, but in a higher layer, definition asan information element may be performed.

In the present invention, an identity, an identifier, and identificationare referred to as an ID (identifier, identification sign, andidentification number). As an ID (UEID) configured so as to beterminal-specific, a cell radio network temporary identifier (C-RNTI), asemi-persistent scheduling C-RNTI (SPS C-RNTI), a Temporary C-RNTI, aTPC-PUSCH RNTI, a TPC-PUCCH RNTI, and a random value for contentionresolution are provided. The IDs are used in a unit of a cell. The IDsare configured by the higher layer processing unit 101.

The higher layer processing unit 101 configures various identifiers forthe terminal device 2. The higher layer processing unit 101 notifies theterminal device 2 of the various configured identifiers through thetransmission unit 107. For example, the higher layer processing unit 101configures the RNTI and notifies the terminal device 2 of the configuredRNTI. The higher layer processing unit 101 configures a physical layercell ID, a virtual cell ID, or an ID corresponding to the virtual cellID, and notifies the terminal device 2. For example, as the IDcorresponding to the virtual cell ID, IDs (PUSCH ID, PUCCH ID,scrambling initialization ID, reference signal ID (RSID), and the like)which may be configured so as to be specific to a physical channel areprovided. The physical layer cell ID or the virtual cell ID may be usedin generating a physical channel and a sequence of a physical signal.

The higher layer processing unit 101 generates downlink controlinformation (DCI) of which notification is performed on a physicaldownlink control channel (PDCCH) or an enhanced physical downlinkcontrol channel (EPDCCH), and generates control information forcontrolling the reception unit 105 and the transmission unit 107. Thehigher layer processing unit 101 outputs the generated information tothe control unit 103.

The higher layer processing unit 101 generates the control informationfor controlling the reception unit 105 and the transmission unit 107based on uplink control information (UCI) of which notification isperformed on a physical uplink control channel (PUCCH) from the terminaldevice 2, and a situation of a buffer of which notification is performedfrom the terminal device 2, or various types of configurationinformation (RRC message, system information, parameter, and informationelement) of each terminal device 2, which are configured by the higherlayer processing unit 101. The higher layer processing unit 101 outputsthe generated information to the control unit 103. The UCI includes atleast one of ACK/NACK, a scheduling request (SR), and channel stateinformation (CSI). The CSI includes at least one of the CQI, the PMI,and the RI.

The higher layer processing unit 101 configures transmitted power of anuplink signal (PRACH, PUCCH, PUSCH, UL DMRS, P-SRS, and A-SRS), and aparameter relating to the transmitted power. The higher layer processingunit 101 transmits transmitted power of a downlink signal (CRS, DL DMRS,CSI-RS, PDSCH, PDCCH/EPDCCH, and the like), and a parameter relating tothe transmitted power, to the terminal device 2 through the transmissionunit 107. That is, the higher layer processing unit 101 transmitsinformation regarding power control of the uplink and the downlink tothe terminal device 2 through the transmission unit 107. In other words,the higher layer processing unit 101 generates information regardingtransmitted power control of the base station apparatus 1 and theterminal device 2. For example, the higher layer processing unit 101transmits a parameter relating to transmitted power of the base stationapparatus 1, to the terminal device 2.

The higher layer processing unit 101 transmits parameters used forconfiguring the maximum transmitted power P_(CMAX, c) and the totalmaximum output power P_(CMAX) of the terminal device 2, to the terminaldevice 2. The higher layer processing unit 101 transmits informationregarding transmitted power control of various physical channels, to theterminal device 2.

The higher layer processing unit 101 sets transmitted power of theterminal device 2 in accordance with information indicating theinterference quantity from the adjacent base station apparatus,information indicating the interference quantity of which notificationis performed from the adjacent base station apparatus, and which isapplied to the adjacent base station apparatus 1, quality of a channel,which is input from the channel measurement unit 109, and the like. Thehigher layer processing unit 101 sets transmitted power of the terminaldevice 2 so as to cause a PUSCH and the like to satisfy predeterminedchannel quality, considering interference to the adjacent base stationapparatus 1. The higher layer processing unit 101 transmits informationindicating the above setting, to the terminal device 2 through thetransmission unit 107.

Specifically, the higher layer processing unit 101 transmits standardpowers (P_(O) _(_) _(NOMINAL) _(_) _(PUSCH), P_(O) _(_) _(NOMINAL) _(_)_(PUCCH)) for a PUSCH and PUCCH, a pathloss compensation coefficient(attenuation coefficient) α, power offset for Message 3, power offsetdefined for each PUCCH format, and the like in system information. Theabove-described pieces of information are transmitted as information(information of a shared parameter relating to uplink power control)shared between terminal devices 2 or information which is configured asa common parameter between terminal devices 2. At this time, the poweroffset of PUCCH format 3 and power offset of delta-PUCCH format 1bCS maybe added and notification thereof may be performed. Notification of theinformation of the shared parameters may be performed in a RRC message.

The higher layer processing unit 101 performs notification of terminaldevice-specific PUSCH power P₀ _(_) _(UE) _(_) _(PUSCH), a parameter(deltaMCS-Enabled) for an instruction of whether or not a delta-MCS iseffective, a parameter (accumulationEnabled) for an instruction ofwhether or not accumulation is effective, terminal device-specific PUCCHpower P₀ _(_) _(UE) _(_) _(PUCCH), P-SRS power offset P_(SRS) _(_)_(OFFSET)(0), and a filter coefficient, as information which may beconfigured for each terminal device 2 (information of a dedicatedparameter relating to uplink power control) in the RRC message. At thistime, notification of power offset of transmission diversity in eachPUCCH format, and A-SRS power offset P_(SRS) _(_) _(OFFSET)(1) may beperformed. α described herein is a coefficient (attenuation coefficient,pathloss compensation coefficient) which is used for setting thetransmitted power along with a pathloss value, and indicates the extentfor compensating the pathloss. In other words, α is a coefficient fordetermining the extent that the transmitted power is increased ordecreased in accordance with pathloss (that is, the degree oftransmitted power to be compensated). α is normally set to have a valueof 0 to 1. If α is 0, compensation of power in accordance with pathlossis not performed. If α is 1, compensation of the transmitted power ofthe terminal device 2 is performed so as to cause no influence of thepathloss to occur in the base station apparatus 1. The pieces ofinformation may be transmitted to the terminal device 2 asreconfiguration information. The shared parameter and the dedicatedparameter may be independently configured in the primary cell and thesecondary cell, or in a plurality of serving cells.

In a case where the reception unit 105 receives function information ofthe terminal device 2 from the terminal device 2, the higher layerprocessing unit 101 performs various configurations based on thereceived function information of the terminal device 2. For example, thehigher layer processing unit 101 determines a carrier frequency of anuplink and a carrier frequency of a downlink, from a band (EUTRAOperating Band) supported by the terminal device 2, based on thereceived function information of the terminal device 2. The higher layerprocessing unit 101 determines whether or not the MIMO communication isperformed for the terminal device 2, based on the received functioninformation of the terminal device 2. The higher layer processing unit101 determines whether or not the carrier aggregation is performed,based on the received function information of the terminal device 2. Thehigher layer processing unit 101 determines whether or not the carrieraggregation is performed by using component carriers having differentframe structure types, based on the received function information of theterminal device 2. That is, the higher layer processing unit 101determines whether or not a secondary cell is configured, and determinesvarious parameters used for the secondary cell. The higher layerprocessing unit 101 notifies the terminal device 2 of the determinedinformation. Notification of the information regarding the carrierfrequency may be performed in the RRC message. That is, notification ofthe information regarding the carrier frequency may be in the systeminformation. Notification of the information regarding the carrierfrequency, with being included in mobility control information may beperformed. Notification of the information regarding the carrierfrequency may be performed as RRC information by a higher layer.

In a case where the higher layer processing unit 101 configures asecondary cell for the terminal device 2, the higher layer processingunit 101 assigns a cell index except for a specific value (for example,“0” or information bit corresponding to “0”) to the secondary cell, andtransmits the configuration information thereof to the terminal device2. In a case where the secondary cell is configured, the terminal device2 considers the cell index of the primary cell as the specific value.

The higher layer processing unit 101 may configure transmitted power ofa downlink signal/uplink signal, or parameters relating to thetransmitted power for each terminal device 2. The higher layerprocessing unit 101 may configure transmitted power of a commondownlink/uplink signal between terminal devices 2, or parametersrelating to the transmitted power. The higher layer processing unit 101may transmit information regarding the parameters to the terminal device2, as information (information of the parameter relating to the uplinkpower control) regarding the uplink power control, and/or information(information of the parameter relating to the downlink power control)regarding the downlink power control. The information of the parameterrelating to the uplink power control and the information of theparameter relating to the downlink power control include at least oneparameter, and are transmitted to the terminal device 2.

The higher layer processing unit 101 configures various IDs relating tovarious physical channels/physical signals. The higher layer processingunit 101 outputs information regarding the configuration of the IDs tothe reception unit 105 and the transmission unit 107 through the controlunit 103. For example, the higher layer processing unit 101 configuresthe value of the RNTI (UEID) for scrambling CRC included in the downlinkcontrol information format.

The higher layer processing unit 101 may configure values of variousidentifiers such as the cell radio network temporary identifier(C-RNTI), the Temporary C-RNTI, Paging-RNTI (P-RNTI), a random accessRNTI (RA-RNTI), the semi-persistent scheduling C-RNTI (SPS C-RNTI), anda system information RNTI (SI-RNTI).

The higher layer processing unit 101 configures the value of an ID suchas a physical cell ID, a virtual cell ID, and a scramblinginitialization ID. The configuration information is output to eachprocessing unit through the control unit 103. The configurationinformation may be transmitted to the terminal device 2, as a RRCmessage or system information, dedicated information specific to aterminal device, and an information element. Some of RNTIs may betransmitted by using a MAC control element (CE).

The control unit 103 generates a control signal for controlling thereception unit 105 and the transmission unit 107, based on controlinformation from the higher layer processing unit 101. The control unit103 outputs the generated control signal to the reception unit 105 andthe transmission unit 107, so as to control the reception unit 105 andthe transmission unit 107.

The reception unit 105 separates, demodulates, and decodes a receptionsignal which has been received from the terminal device 2 through thetransmit/receive antenna 111, in accordance with the control signalinput from the control unit 103. The reception unit 105 outputs thedecoded information to the higher layer processing unit 101. The radioreception portion 1057 converts (down-converts) the frequency of thesignal of an uplink which has been received through the transmit/receiveantenna 111 into an intermediate frequency (IF), and removes anunnecessary frequency component. The radio reception portion 1057controls an amplification level so as to appropriately maintain thesignal level, performs orthogonal demodulation, and converts the analogsignal subjected to orthogonal demodulation, into a digital signal. Suchdemodulation and conversion is performed based on the same phasecomponent and the orthogonal component of the received signal. The radioreception portion 1057 removes a portion corresponding to a guardinterval (GI) from the converted digital signal. The radio receptionportion 1057 performs Fast Fourier Transform (FFT) on a signal obtainedby removing the guard interval. The radio reception portion 1057extracts the signal in the frequency domain, and outputs the extractedsignal to the demultiplexing portion 1055.

The demultiplexing portion 1055 separates the signal input from theradio reception portion 1057 into signals of a PUCCH, a PUSCH, a ULDMRS, a SRS, and the like. The separation is performed based onassignment information of radio resources. The assignment information isdetermined in advance by the base station apparatus 1, and each terminaldevice 2 is notified of the assignment information. The demultiplexingportion 1055 performs channel compensation of the PUCCH and the PUSCHfrom an estimated value of the channel, which is input from the channelmeasurement unit 109. The demultiplexing portion 1055 outputs theseparated UL DMRS and SRS to the channel measurement unit 109.

The demodulation portion 1053 performs inverse discrete Fouriertransform (IDFT) on the PUSCH, and acquires modulation symbols. Thedemodulation portion 1053 demodulates the reception signal with themodulation symbols of the PUCCH and the PUSCH, by using a modulationscheme which is determined in advance, or of which each terminal device2 is notified in advance in the downlink control information by the basestation apparatus 1. Such a modulation scheme includes binary phaseshift keying (BPSK), quadrature phase shift keying (QPSK), 16 quadratureamplitude modulation (16QAM), 64 quadrature amplitude modulation(64QAM), and the like.

The decoding portion 1051 decodes coded bits of the PUCCH and the PUSCH,which have been demodulated, at a coding rate of the predeterminedcoding scheme. The coding rate is determined in advance, or the basestation apparatus 1 notifies the terminal device 2 of the coding rate inadvance in the uplink grant (UL grant). The decoding portion 1051outputs the decoded data information and the decoded uplink controlinformation to the higher layer processing unit 101.

The channel measurement unit 109 measures the estimated value of thechannel, the quality of the channel, and the like, based on the uplinkdemodulation reference signal (UL DMRS) input from the demultiplexingportion 1055, and the SRS. The channel measurement unit 109 outputs aresult of the measurement to the demultiplexing portion 1055 and thehigher layer processing unit 101. The channel measurement unit 109measures received power of signals from a first signal to the n-thsignal, and/or reception quality thereof. The channel measurement unit109 outputs a result of the measurement to the demultiplexing portion1055 and the higher layer processing unit 101.

The transmission unit 107 generates a reference signal of a downlink(downlink reference signal), based on the control signal input from thecontrol unit 103. The transmission unit 107 codes and modulates datainformation and downlink control information input from the higher layerprocessing unit 101. The transmission unit 107 performs multiplexing onthe PDCCH (EPDCCH), the PDSCH, and the downlink reference signal usingthe DCI format. The transmission unit 107 transmits a downlink signalobtained by multiplexing to the terminal device 2 through thetransmit/receive antenna 111. The transmission unit transmits the PDCCHby using a first DCI format or a second DCI format.

The coding portion 1071 performs coding such as turbo-coding,convolutional coding, and block coding, on the downlink controlinformation input from the higher layer processing unit 101, and datainformation. The modulation portion 1073 modulates the coded bits byusing a modulation scheme such as QPSK, 16QAM, and 64QAM. The downlinkreference signal generation portion 1079 performs generation as adownlink reference signal with a sequence known by the terminal device2. The downlink reference signal is obtained by using a rule which isdetermined based on a cell identifier (Cell ID, Cell Identity, CellIdentifier, Cell Identification), and the like for identifying the basestation apparatus 1. The multiplexing portion 1075 performs multiplexingon the modulated channel and the generated downlink reference signal.

The radio transmission portion 1077 performs Inverse Fast FourierTransform (IFFT) on the multiplexed modulation symbol, and performsmodulation of the OFDM scheme. The radio transmission portion 1077 addsa guard interval to OFDM symbols obtained by OFDM modulation, andgenerates a baseband digital signal. The radio transmission portion 1077converts the baseband digital signal into an analog signal, andgenerates the same-phase component and the orthogonal component of anintermediate frequency, from the analog signal. The radio transmissionportion 1077 removes an extra frequency component from the intermediatefrequency band, and converts (up-converts) a signal having anintermediate frequency into a signal having a high frequency. The radiotransmission portion 1077 removes an extra frequency component,amplifies power, and outputs the signal to the transmit/receive antenna111 so as to perform transmission.

FIG. 2 is a schematic block diagram illustrating a configuration of theterminal device 2 according to the embodiment. As illustrated in FIG. 2,the terminal device 2 includes a higher layer processing unit 201, acontrol unit 203, a reception unit 205, a transmission unit 207, achannel measurement unit 209, and a transmit/receive antenna 211. Thereception unit 205 includes a decoding portion 2051, a demodulationportion 2053, a demultiplexing portion 2055, and a radio receptionportion 2057. Reception processing of the terminal station apparatus 2is performed by the higher layer processing unit 201, the control unit203, the reception unit 205, and the transmit/receive antenna 211. Thetransmission unit 207 includes a coding portion 2071, a modulationportion 2073, a multiplexing portion 2075, and a radio transmissionportion 2077. Transmission processing of the terminal device 2 isperformed by the higher layer processing unit 201, the control unit 203,the transmission unit 207, and the transmit/receive antenna 211.

The higher layer processing unit 201 outputs data information of anuplink, which is generated by an operation of a user, and the like, tothe transmission unit. The higher layer processing unit 201 performsprocessing of a medium access control (MAC) layer, a packet dataconvergence protocol (PDCP) layer, a radio link control (RLC) layer, anda radio resource control (RRC) layer.

The higher layer processing unit 201 manages various types ofconfiguration information of the terminal device 2. The higher layerprocessing unit 201 generates information assigned to each channel ofthe uplink, and outputs the generated information to the transmissionunit 207. The higher layer processing unit 201 generates controlinformation for controlling the reception unit 205 and the transmissionunit 207, based on downlink control information (DCI) of whichnotification is performed on a PDCCH from the base station apparatus 1,and various types of configuration information of the terminal device 2,which are managed by the higher layer processing unit 201 in which radioresource control information of which notification is performed on aPDSCH is configured. The higher layer processing unit 201 outputs thegenerated control information to the control unit 203. The higher layerprocessing unit 201 sets various parameters (information elements andRRC messages) of each signal, based on pieces of information frominformation regarding a first configuration of which notification isperformed from the base station apparatus 1, to information regardingthe n-th configuration. The higher layer processing unit 201 generatesinformation set described above, and outputs the generated informationto the transmission unit 207 through the control unit 203. Whenconnection with the base station apparatus 1 is established, the higherlayer processing unit 201 generates function information of the terminaldevice 2, outputs the generated function information to the transmissionunit 207 through the control unit 203, and notifies the base stationapparatus 1 thereof. After the connection with the base stationapparatus 1 is established, the higher layer processing unit 201 maynotify the base station apparatus 1 of the function information.

The function information may include information (RF-Parameters)regarding a RF parameter. The information regarding the RF parameter mayinclude information (1st SupportedBandCombination) indicating a bandsupported by the terminal device 2. The information regarding the RFparameter may include information (SupportedBandCombinationExt)indicating a band supporting the carrier aggregation and/or MIMO. Theinformation regarding the RF parameter may include information (2ndSupportedBandConbination) indicating a band which supports a function ofperforming a plurality of timing advances between bands which aresimultaneously aggregated in the terminal device 2, or of performingsimultaneous transmission and reception between bands. The bands may belisted. The value (entry) indicated by plural pieces of listedinformation may be used commonly (may indicates the same).

Whether each band (bandE-UTRA, FreqBandIndicator, and E-UTRA OperatingBand) supported by the terminal device 2 supports half duplex may beindicated. In a band in which half duplex is not supported, full duplexis supported.

Whether a band supported by the terminal device 2 supports the carrieraggregation and/or MIMO in an uplink may be indicated.

Whether a band supported by the terminal device 2 supports the carrieraggregation and/or MIMO in a downlink may be indicated.

The information regarding the RF parameter may include informationindicating a band which supports TDD-FDD carrier aggregation. Theabove-described bands may be listed.

The information regarding the RF parameter may include informationindicating whether a function of performing simultaneous transmissionand reception between bands which support TDD-FDD carrier aggregation issupported.

The information regarding the RF parameter may include informationindicating whether or not simultaneous transmission and reception isperformed between bands of different duplex modes.

In a case where a function which is not supported is present amongfunctions included in the function information, the higher layerprocessing unit 201 may not set information indicating whether or notthe function is supported, in the function information. The base stationapparatus 1 considers the function which is not set in the functioninformation not to be supported by the terminal device 2, and performsvarious configurations. The information indicating whether or not thefunction is supported may be information indicating the function issupported.

If the function which is not supported is present, the higher layerprocessing unit 201 sets a specific value (for example, “0”) indicatingnot to be supported or information (for example, “not supported”,“disable”, “FALSE”, and the like), regarding the function. The higherlayer processing unit 201 may notify the base station apparatus 1 offunction information including the above information.

If the function which is supported is present, the higher layerprocessing unit 201 sets a specific value (for example, “1”) indicatingto be supported or information (for example, “supported”, “enable”,“TRUE”, and the like), regarding the function. The higher layerprocessing unit 201 may notify the base station apparatus 1 of functioninformation including the above information.

In a case where there is no a function of performing simultaneoustransmission and reception between bands which may be simultaneouslyaggregated, the higher layer processing unit 201 sets a specific valueor information indicating that the function is not supported, ininformation (simultaneousRx-Tx) indicating whether or not the functionof performing simultaneous transmission and reception between bandswhich may be simultaneously aggregated is supported. In addition, theinformation indicating whether or not the function of performingsimultaneous transmission and reception between bands which may besimultaneously aggregated is supported may be not set in the functioninformation.

The higher layer processing unit 201 acquires the following pieces ofinformation from the reception unit 205. The pieces of informationinclude information indicating a sounding subframe, and a bandwidth ofthe radio resources reserved for transmitting the SRS in the soundingsubframe; information indicating a subframe in which the periodic SRS ofwhich the terminal device 2 is notified by the base station apparatus 1,a frequency band, and the quantity of cycling shift used in CAZACsequences of the periodic SRS; and information indicating a frequencyband for transmitting the aperiodic SRS of which the terminal device 2is notified by the base station apparatus 1, and the quantity of cyclingshift used in CAZAC sequences of the aperiodic SRS. The soundingsubframe (SRS subframe, SRS transmission subframe) is a subframe forreserving radio resources which are used for transmitting the SRSreported by the base station apparatus 1.

The higher layer processing unit 201 controls SRS transmission inaccordance with the information. Specifically, the higher layerprocessing unit 201 controls the transmission unit 207 to transmit aperiodic SRS in accordance with information regarding the periodic SRSonce or periodically. In a case where transmission of the aperiodic SRSin a SRS request (SRS indicator) input from the reception unit 205 isrequired, the higher layer processing unit 201 transmits the aperiodicSRS in accordance with information regarding the aperiodic SRS, thepredetermined number of times (for example, one time).

The higher layer processing unit 201 controls transmitted power of thePRACH, the PUCCH, the PUSCH, the periodic SRS, and the aperiodic SRS,based on information regarding transmitted power control of variousuplink signals transmitted from the base station apparatus 1.Specifically, the higher layer processing unit 201 configures thetransmitted power of the various uplink signals, based on informationregarding various types of uplink power control acquired from thereception unit 205. For example, the transmitted power of the SRS iscontrolled based on P₀ _(_) _(PUSCH), α, power offset P_(SRS) _(_)_(OFFSET)(0) (first power offset (pSRS-Offset)) for the periodic SRS,power offset P_(SRS) _(_) _(OFFSET)(1) (second power offset(pSRS-OffsetAp)) for the aperiodic SRS, and a TPC command. The higherlayer processing unit 201 performs switching between the first poweroffset and the second power offset, in accordance with which theperiodic SRS or the aperiodic SRS is provided for P_(SRS) _(_)_(OFFSET).

In a case where third power offset is configured for the periodic SRSand/or aperiodic SRS, the higher layer processing unit 201 setstransmitted power, based on the third power offset. The third poweroffset may be configured so as to have a value in a range wider thanthat of the first power offset or the second power offset. The thirdpower offset may be configured for each of the periodic SRS and theaperiodic SRS. That is, the information of parameters relating to theuplink power control corresponds to an information element or a RRCmessage which includes parameters relating to control of transmittedpower of various uplink physical channels.

In a case where the sum of transmitted power of a first uplink referencesignal and transmitted power of a physical uplink shared channel exceedsthe maximum transmitted power (for example, P_(CMAX) or P_(CMAX, c))configured in the terminal device 2, in a certain serving cell or acertain subframe, the higher layer processing unit 201 outputinstruction information to the transmission unit 207 through the controlunit 203, so as to transmit the physical uplink shared channel.

In a case where the sum of transmitted power of the first uplinkreference signal and transmitted power of a physical uplink controlchannel exceeds the maximum transmitted power (for example, P_(CMAX) orP_(CMAX, c)) configured in the terminal device 2, in a certain servingcell or a certain subframe, the higher layer processing unit 201 outputinstruction information to the transmission unit 207 through the controlunit 203, so as to transmit the physical uplink control channel.

In a case where the sum of transmitted power of a second uplinkreference signal and transmitted power of the physical uplink sharedchannel exceeds the maximum transmitted power configured in the terminaldevice 2, in a certain serving cell or a certain subframe, the higherlayer processing unit 201 output instruction information to thetransmission unit 207 through the control unit 203, so as to transmitthe physical uplink shared channel.

In a case where the sum of transmitted power of the second uplinkreference signal and transmitted power of the physical uplink controlchannel exceeds the maximum transmitted power configured in the terminaldevice 2, in a certain serving cell (for example, serving cell c) or acertain subframe (for example, subframe i), the higher layer processingunit 201 output instruction information to the transmission unit 207through the control unit 203, so as to transmit the physical uplinkcontrol channel.

In a case where transmission of a plurality of physical channels occursat the same timing (for example, subframe), the higher layer processingunit 201 may control transmitted power of various physical channels orcontrol transmission of the various physical channels, in accordancewith the priorities of the various physical channels. The higher layerprocessing unit 201 outputs control information thereof to thetransmission unit 207 through the control unit 203.

In a case where carrier aggregation is performed by using a plurality ofcomponent carriers which respectively correspond to a plurality ofserving cells or a plurality of serving cells, the higher layerprocessing unit 201 may control transmitted power of various physicalchannels or control transmission of the various physical channels, inaccordance with the priorities of the various physical channels.

The higher layer processing unit 201 may control transmission of variousphysical channels which are to be transmitted from a cell, in accordancewith the priority of the cell. The higher layer processing unit 201outputs control information thereof to the transmission unit 207 throughthe control unit 203.

The higher layer processing unit 201 outputs instruction information tothe transmission unit 207 through the control unit 203, based oninformation regarding a configuration of the uplink reference signal ofwhich notification is performed from the base station apparatus 1, forexample, such that the uplink reference signal is generated. That is thereference signal control unit 2013 outputs the information regarding theconfiguration of the uplink reference signal, to the uplink referencesignal generation unit 2079 through the control unit 203.

The control unit 203 generates a control signal for controlling thereception unit 205 and the transmission unit 207, based on the controlinformation from the higher layer processing unit 201. The control unit203 outputs the generated control signal to the reception unit 205 andthe transmission unit 207, and thus controls the reception unit 205 andthe transmission unit 207.

The reception unit 205 separates, demodulates, and decodes a receptionsignal which is received from the base station apparatus 1 through thetransmit/receive antenna 211, in accordance with the control signalinput from the control unit 203. The reception unit 205 outputsinformation obtained by the decoding to the higher layer processing unit201. The reception unit receives a PDCCH which has been transmitted byusing the first DCI format or the second DCI format.

The reception unit 205 performs appropriate reception processing inaccordance with whether or not information regarding a firstconfiguration and/or information regarding a second configuration isreceived. For example, in a case where either of the informationregarding the first configuration and the information regarding thesecond configuration is received, the reception unit 205 detects a firstcontrol information field from the received downlink control informationformat. In a case where the information regarding the firstconfiguration and the information regarding the second configuration arereceived, the reception unit 205 detects a second control informationfield from the received downlink control information format.

The radio reception portion 2057 converts (down-converts) the frequencyof the signal of a downlink which has been received through the receiveantenna into an intermediate frequency, and removes an unnecessaryfrequency component. The radio reception portion 2057 controls anamplification level so as to appropriately maintain the signal level,and performs orthogonal demodulation based on the same phase componentand the orthogonal component of the received signal. The radio receptionportion 2057 converts the analog signal subjected to orthogonaldemodulation, into a digital signal. The radio reception portion 2057removes a portion corresponding to a guard interval from the converteddigital signal. The radio reception portion 2057 performs Fast FourierTransform on a signal obtained by removing the guard interval, and thusextracts a signal in the frequency domain.

The demultiplexing portion 2055 separates the extracted signal into aPDCCH, a PDSCH, and a downlink reference signal (DL-RS). The separationis performed based on assignment information and the like of radioresources of which notification is performed in downlink controlinformation. The demultiplexing portion 2055 performs compensation of apath of the PDCCH and the PDSCH, based on an estimated value of thepath, which is input from the channel measurement unit 209. Thedemultiplexing portion 2055 outputs the downlink reference signalobtained by the separation, to the channel measurement unit 209.

The demodulation portion 2053 performs demodulation of the QPSKmodulation scheme, on the PDCCH transmitted by using the DCI format. Thedemodulation portion 2053 outputs a result obtained by the demodulation,to the decoding portion 2051. In a case where decoding of the PDCCH isexamined, and success of decoding is determined, the decoding portion2051 outputs the decoded downlink control information (DCI) to thehigher layer processing unit 201. The demodulation portion 2053 performsdemodulation of the modulation scheme of which notification is performedin the downlink control information, such as QPSK, 16QAM, and 64QAM onthe PDSCH. The demodulation portion 2053 outputs a result obtained bythe demodulation, to the decoding portion 2051. The decoding portion2051 performs decoding with the coding rate of which notification isperformed in the downlink control information, and outputs datainformation obtained by decoding, to the higher layer processing unit201.

The channel measurement unit 209 measures the pathloss of the downlinkbased on the downlink reference signal input from the demultiplexingportion 2055, and outputs the measured pathloss to the higher layerprocessing unit 201. The channel measurement unit 209 calculates anestimated value of a channel of a downlink, based on the downlinkreference signal, and outputs the calculated value to the demultiplexingportion 2055. The channel measurement unit 209 measures received powerof a first signal and/or a second signal, or measures reception qualitythereof, in accordance with various types of information regardingmeasurement, of which notification is performed from the referencesignal control unit 2013 through the control unit 203, and various typesof information regarding a measurement report. The channel measurementunit 209 outputs the result thereof to the higher layer processing unit201. In a case where an instruction of performing a channel evaluationof the first signal and/or the second signal is performed, the channelmeasurement unit 209 may output a result regarding the channelevaluation of each of the signals, to the higher layer processing unit201. Here, the first signal or the second signal are reference signals(pilot signals, pilot channels, base signals). In addition to the firstsignal or the second signal, a third signal or a fourth signal may beprovided. That is, the channel measurement unit 209 measures channels ofone or more signals. The channel measurement unit 209 configures asignal for measuring the channel, in accordance with the controlinformation of which notification is performed from the higher layerprocessing unit 201 through the control unit 203.

In a certain cell (first cell), in a case where an uplink subframe inwhich uplink transmission is required is generated, and thus measurementof CRS or CSI-RS is not possible in the same subframe of a cell (secondcell) different from the certain cell, the channel measurement unit 209may perform processing except for a subframe in which measurement of anaverage of measurement results (received power, reception quality,channel quality, and the like) in the second cell is not possible. Inother words, the channel measurement unit 209 may calculate an averagevalue of the measurement results (received power, reception quality,channel quality, and the like), only by using the received CRS orCSI-RS. The channel measurement unit 209 may transmit the calculationresult thereof (indicator or information corresponding to thecalculation result) to the base station apparatus 1 through thetransmission unit 207.

The transmission unit 207 generates an uplink demodulation referencesignal (UL DMRS) and/or a sounding reference signal (SRS), based on thecontrol signal (control information) input from the control unit 203.The transmission unit 207 codes and modulates data information inputfrom the higher layer processing unit 201, and performs multiplexing ofa PUCCH, a PUSCH, and the generated UL DMRS and/or the generated SRS.The transmission unit 207 adjusts transmitted power of the PUCCH, thePUSCH, the UL DMRS, and the SRS, and transmits the adjusted transmittedpower to the base station apparatus 1 through the transmit/receiveantenna 211.

In a case where information regarding a measurement result is outputfrom the higher layer processing unit 201, the transmission unit 207transmits the output information, to the base station apparatus 1through the transmit/receive antenna 211.

In a case where channel state information which is a result regardingthe channel evaluation is output from the higher layer processing unit201, the transmission unit 207 performs feedback of channel stateinformation to the base station apparatus 1. That is, the higher layerprocessing unit 201 generates channel state information (CSI, CQI, PMI,RI) based on a measurement result of which notification is performedfrom the channel measurement unit 209, and performs feedback to the basestation apparatus 1 through the control unit 203.

If a predetermined grant (or a predetermined downlink controlinformation format) is detected in the reception unit 205, thetransmission unit 207 transmits an uplink signal corresponding to thepredetermined grant in the first uplink subframe among subframessubsequent to a predetermined subframe from a subframe in which thegrant is detected. For example, if the grant is detected in the subframei, the uplink signal may be transmitted in the first uplink subframeamong subframes subsequent to a subframe (i+k).

In a case where a transmission subframe of the uplink signal is thesubframe i, the transmission unit 207 sets transmitted power of theuplink signal, based on a power control adjustment value obtained by aTPC command which is received in a subframe (i−k). Here, the powercontrol adjustment value f(i) (or g(i)) is configured based on acorrected value or an absolute value which is correlated with a valueset in the TPC command. In a case where the accumulation is effective,corrected values correlated with the value set in the TPC command areaccumulated, and the accumulation result is applied as the power controladjustment value. In a case where the accumulation is not effective, asingle absolute value which is correlated with a value set in the TPCcommand is applied as the power control adjustment value.

In a case where either of the information regarding the firstconfiguration and the information regarding the second configuration isreceived in the reception unit 205, the transmission unit 207 setstransmitted power based on a parameter relating to the first uplinkpower control. In a case where the information regarding the firstconfiguration and the information regarding the second configuration arereceived in the reception unit 205, the transmission unit 207 sets thetransmitted power based on a parameter relating to the second uplinkpower control, and transmits the uplink signal.

The coding portion 2071 performs coding such as turbo-coding,convolutional coding, and block coding, on the uplink controlinformation input from the higher layer processing unit 201, and datainformation. The modulation portion 2073 modulates the coded bits inputfrom the coding portion 2071, by using a modulation scheme such as BPSK,QPSK, 16QAM, and 64QAM.

The uplink reference signal generation unit 2079 generates an uplinkreference signal based on information regarding the configuration of theuplink reference signal. That is, the uplink reference signal generationunit 2079 generates CAZAC sequences known by the base station apparatus1. The CAZAC sequences are obtained by using a rule which is determinedbased on a cell identifier for identifying the base station apparatus 1,a bandwidth for assigning an uplink demodulation reference signal, thefirst uplink reference signal, and the second uplink reference signal,and the like. The uplink reference signal generation unit 2079 adds thecycling shift to the CAZAC sequences of the generated uplinkdemodulation reference signal, the first uplink reference signal, andthe second uplink reference signal, based on the control signal inputfrom the control unit 203.

The uplink reference signal generation unit 2079 may initialize basesequences of the uplink demodulation reference signal, and/or thesounding reference signal, and the uplink reference signal, based onpredetermined parameters. The predetermined parameters may be the sameas each other in the reference signals. The predetermined parameters maybe configured independently in the reference signals. That is, theuplink reference signal generation unit 2079 may initialize the basesequences of the reference signals by using the same parameter, as longas there is no parameter which is independently configured.

The multiplexing portion 2075 arranges modulation symbols of the PUSCHin parallel with each other, based on the control signal input from thecontrol unit 203, so as to perform discrete Fourier transform (DFT), andperforms multiplexing of the PUCCH, the signal of the PUSCH, and thegenerated UL DMRS, and the generated SRS.

The radio transmission portion 2077 performs Inverse Fast FourierTransform on the multiplexed signals, and performs modulation of theSC-FDMA scheme. The radio transmission portion 2077 adds a guardinterval to SC-FDMA symbols obtained by SC-FDMA modulation, andgenerates a baseband digital signal. The radio transmission portion 2077converts the baseband digital signal into an analog signal, andgenerates the same-phase component and the orthogonal component of anintermediate frequency, from the analog signal. The radio transmissionportion 2077 removes an extra frequency component from the intermediatefrequency band, and converts (up-converts) a signal having anintermediate frequency into a signal having a high frequency (radiofrequency). The radio transmission portion 2077 removes an extrafrequency component, amplifies power, and outputs the signal to thetransmit/receive antenna 211 so as to perform transmission.

In the embodiment, the case where the carrier aggregation is configured(secondary cell is configured), and the case where the PUCCH istransmitted and received in the primary cell are described. However, itis not limited thereto. In the case where the carrier aggregation isconfigured, HARQ-ACK corresponding to the PDSCH in the secondary cellmay be transmitted and received in the secondary cell. At this time, ina case where the carrier aggregation is configured, and the carrieraggregation of the uplink is not configured, that is, in a case wherethe secondary cell is configured without accordance with theconfiguration of the uplink component carrier, the HARQ-ACKcorresponding to the PDSCH in the secondary cell is transmitted andreceived in the primary cell. At this time, the above process may beperformed by using the transmission and reception procedure of theHARQ-ACK which is described in the embodiment. Even in a case where theserving cell in which the PUCCH is transmitted and received is a servingcell other than the primary cell (for example, some (one) secondarycells in a secondary cell group), the above process may be performed byusing the transmission and reception procedure of the HARQ-ACK which isdescribed in the embodiment. At this time, the primary cell in theembodiment is rewritten to, for example, some secondary cells, and thussimilar effects can be exhibited.

In the embodiment, the reception processing may include detectionprocessing (detection). The reception processing may includedemodulation processing (demodulation). The reception processing mayinclude decoding processing (decode, decoding).

In the terminal device 2, the priorities of the physicalchannels/physical signals to be transmitted may be configured or definedin advance, in accordance with the type of the physical channel.

In the embodiment, the terminal device 2 may report a measurement resultof the received power to the base station apparatus 1 based on theCSI-RS or a discovery reference signal (DRS). The terminal device 2 mayperform periodically reporting. The terminal device 2 may perform thereporting in a case where a certain condition is satisfied.

In the embodiment, in a case where the terminal device 2 measures thereceived power based on the CSI-RS or the DRS, the terminal device 2 mayperform transmitted power control of the uplink signal based on thereceived power. That is, the terminal device 2 may determine downlinkpathloss based on the received power.

In the embodiment, in a case where the sum of transmitted power of thevarious uplink signals, which includes transmitted power of the firstuplink reference signal and/or the second uplink reference signalexceeds the maximum transmitted power configured in the terminal device2, the terminal device 2 may not transmit the first uplink referencesignal and/or the second uplink reference signal.

If a TDD UL/DL configuration (first TDD UL/DL configuration) for theuplink transmission reference, and a TDD UL/DL configuration (second TDDUL/DL configuration) for the downlink transmission reference areconfigured, and information regarding the uplink transmitted powercontrol is configured, in a case where subframes having the same typeare configured in the first TDD UL/DL configuration and the second TDDUL/DL configuration, the terminal device 2 sets the uplink power controlof the subframe, based on the parameters relating to the first uplinkpower control. In a case where subframes having different types areconfigured in the first TDD UL/DL configuration and the second TDD UL/DLconfiguration, the uplink power of the subframe is set based on theparameters relating to the second uplink power control.

The flexible subframe is a subframe which is an uplink subframe or adownlink subframe. The flexible subframe is a subframe which is adownlink subframe or a special subframe. The flexible subframe is asubframe which is uplink subframe or the special subframe. That is, theflexible subframe is a subframe which is a first subframe or a secondsubframe. For example, a subframe configured as the flexible subframe isprocessed as the first subframe (for example, uplink subframe) in a caseof Condition 1, and is processed as the second subframe (for example,downlink subframe) in a case of Condition 2.

The flexible subframe may be set based on the first configuration andthe second configuration. For example, in a case where a certainsubframe i is configured as the uplink subframe in the firstconfiguration, and is configured as the downlink subframe in the secondconfiguration, the subframe i functions as the flexible subframe. Theflexible subframe may be configured based on information for performingan instruction of a subframe pattern of the flexible subframe.

A plurality of subframes may be configured not based on two TDD UL/DLconfigurations, but based on one TDD UL/DL configuration and a flexiblesubframe pattern (downlink candidate subframe pattern or uplinkcandidate subframe pattern, addition subframe). The terminal device 2may receive a downlink signal by using a subframe index indicated by aflexible subframe pattern as long as, even when indication as the uplinksubframe in the TDD UL/DL configuration is performed, the uplink signalis transmitted in the subframe. The terminal device 2 may transmit theuplink signal as long as even when indication as the downlink subframein the TDD UL/DL configuration is performed, an instruction oftransmitting the uplink signal in the subframe is performed in advance.An instruction for a specific subframe as an uplink/downlink candidatesubframe may be performed.

If a certain condition is satisfied, the terminal device 2 may recognizeone set of subframes as a subframe set for an uplink, and recognize theother set of subframes as a subframe set for a downlink. Here, thesubframe set for an uplink corresponds to a set of subframes configuredfor transmitting a PUSCH and a PHICH. The downlink subframe setcorresponds to a set of subframes configured for transmitting a PDSCHand HARQ. Information indicating association of subframes with the PUSCHand the PHICH, and information indicating association of subframes withthe PDSCH and the HARQ may be configured in the terminal device 2 inadvance.

In the embodiment, a plurality of subframe sets is configured for oneserving cell (primary cell, secondary cell, carrier frequency,transmission frequency, component carrier). A cell in which a pluralityof subframe sets is configured, and a cell in which a plurality ofsubframe sets is not configured may be provided.

In the embodiment, in a case where two or more subframe sets areindependently configured for one serving cell, the maximum transmittedpower (P_(CMAX), P_(CMAX, c)) for each terminal device 2 may beconfigured for each of the subframe sets. That is, the terminal device 2may configure plural pieces of independent maximum transmitted power tobe plural. That is, plural pieces of maximum transmitted power(P_(CMAX), P_(CMAX, c)) may be set for one serving cell. Plural piecesof the maximum allowable output power (P_(EMAX, c)) may be configuredfor one serving cell.

In a case where resource assignments of various uplink signals are thesame as each other, the base station apparatus 1 may detect the variousuplink signals by using a difference between signal sequences of theuplink signals. That is, the base station apparatus 1 may recognize theuplink signal by using the difference between the signal sequences ofthe received uplink signals. The base station apparatus 1 may determinewhether or not transmission to the base station apparatus 1 isperformed, by using the difference between the signal sequences of thereceived uplink signals.

In a case where an instruction of measuring received power is performedby using the CSI-RS or the DRS from the base station apparatus 1, theterminal device 2 may calculate downlink pathloss based on themeasurement result, and use the calculated downlink pathloss in theuplink transmitted power control.

Here, the measurement of the received power may be also referred toreference signal received power (RSRP) measurement or reception signalpower measurement. Measurement of reception quality may be also referredto reference signal received quality (RSRQ) measurement or receptionsignal quality measurement.

The resource assignment (resource allocation, mapping to resourceelements, mapping to physical resources) of the CSI-RS or the DRS may befrequency-shifted. The frequency shift of the CSI-RS or the DRS may bedetermined based on the physical cell ID. The frequency shift of theCSI-RS or the DRS may be determined based on the virtual cell ID.

For example, if notification of information is not performed from thebase station apparatus 1, the terminal device 2 measures received powerof the first downlink reference signal. Notification of information foran instruction of whether or not received power of the second downlinkreference signal is measured is performed for the terminal device 2 fromthe base station apparatus 1. In a case where the instructioninformation indicates that the received power of the second downlinkreference signal may be measured, the terminal device 2 measures thereceived power of the second downlink reference signal. At this time,the terminal device 2 may measure the received power of the firstdownlink reference signal along with the measurement of the seconddownlink reference signal. In a case where the instruction informationindicates that measuring the received power of the second downlinkreference signal is not possible, the terminal device 2 measures thereceived power of only the first downlink reference signal. Theinstruction information may include information for an instruction ofwhether or not reception quality of the second downlink reference signalis measured. Regardless the instruction information, received power of athird downlink reference signal may be measured.

In a case where two subframe sets are configured for one serving cell,if the second subframe set is set to be a subframe pattern of theflexible subframe, information of instructing the flexible subframe of apattern of a subframe in which the DCI format including the TPC commandfield can be received may be transmitted to the terminal device 2 fromthe base station apparatus 1.

A pattern of a subframe in which a TPC command applicable to the uplinksubframe which belongs to the first subframe set, and a pattern of asubframe in which a TPC command applicable to the uplink subframe whichbelongs to the second subframe set may be respectively configured. Thecorrespondence between the uplink subframe and the downlink subframe inwhich the DCI format including the TPC command for the uplink subframeis transmitted may be managed in a table.

RSRP measurement results may be independent from each other in asubframe set. A RSRP by the CRS received in a downlink subframe of afixation subframe and a RSRP by the CRS received in the flexiblesubframe may be independently measured.

In the embodiment, the descriptions are made by using a resource elementor a resource block as a mapping unit of various uplink signals orvarious downlink signals, and by using a symbol, a subframe, or a radioframe as a transmitting unit in the time direction. However, it is notlimited thereto. Similar effects may be also obtained by using a regionunit and a time unit configured by an arbitrary frequency and timeinstead of the above-described units. In the embodiment, a case wheredemodulation is performed by using a RS subjected to precodingprocessing is described. Furthermore, the descriptions are made by usinga port which is equivalent to the layer of MIMO, as a port correspondingto the RS subjected to the precoding processing. However, it is notlimited thereto. In addition, the present invention is applied to portscorresponding to reference signals which are different from each other,and thus similar effects may be obtained. For example, as the port, aport which is equivalent to an output end after precoding is processed,or a port which is equivalent to a physical antenna (or combination ofphysical antennae) may be used by using Unprecoded (Nonprecoded) RS, notPrecoded RS.

In the embodiment, in a case where only DCI format 3/3A is received in acertain downlink subframe, a correction value (or absolute value)corresponding to a value set in the TPC command field which is includedin DCI format 3/3A is applied to the power control adjustment value forthe transmitted power of a PUSCH which is transmitted in a specificsubframe set, regardless of which subframe set the downlink subframebelongs to. In a case where only DCI format 3/3A is received in acertain downlink subframe, the accumulation of TPC commands included inDCI format 3/3A may be applied to the power control adjustment value forthe transmitted power of a PUSCH which is transmitted in a specificsubframe set. The specific subframe set may be a set of fixationsubframes, a set of flexible subframes, or a set of arbitrary subframes.

In the embodiment, the parameter relating to the uplink power controlcorresponds to the parameter used in the transmitted power control ofthe uplink physical channel/physical signal (PUSCH, PUCCH, PRACH, SRS,DMRS, and the like). The parameter used in the transmitted power controlincludes information regarding switching or (re)configuring of variousparameters which are used in configuring transmitted power of variousuplink physical channels. The parameter relating to the downlinktransmitted power control corresponds to the parameter used in thetransmitted power control of the downlink physical channel/physicalsignal (CRS, UERS (DL DMRS), CSI-RS, PDSCH, PDCCH/EPDCCH, PBCH, PSS/SSS,PMCH, PRS, and the like). The parameter used in the transmitted powercontrol includes information regarding switching or (re)configuring ofvarious parameters which are used in configuring transmitted power ofvarious downlink physical channels.

In the embodiment, the base station apparatus 1 may configure aplurality of virtual cells ID for one terminal device 2. For example,the base station apparatus 1 and a network including at least one basestation apparatus 1 may configure independently virtual cells ID foreach physical channel/physical signal. A plurality of virtual cells IDfor one physical channel/physical signal may be configured. That is, thevirtual cell ID may be set for each configuration of the physicalchannel/physical signal. The virtual cell ID may be shared between aplurality of physical channels/physical signals.

In the descriptions of the embodiment, for example, a case of settingpower includes a case where a value of the power is set. The case ofsetting power includes a case where a value is set in a parameterrelating to the power. A case of calculating power includes a case wherethe value of the power is calculated, and a case of measuring powerincludes a case where the value of the power is measured. A case ofreporting power includes a case where the value of the power isreported. In this manner, the expression of the power appropriatelyincludes the meaning of the value of the power.

In the descriptions of the embodiment, a case where transmission is notperformed includes a case where transmission processing is notperformed. The case where transmission is not performed includes a casewhere a signal for transmission is not generated. The case wheretransmission is not performed includes a case where a signal (orinformation) is generated, but the generated signal (or information) isnot transmitted. A case where reception is not performed includes a casewhere reception processing is not performed. The case where reception isnot performed includes a case where detection processing is notperformed. The case where reception is not performed includes a casewhere decoding or demodulation processing is not performed.

In the descriptions of the embodiment, for example, a case ofcalculating the pathloss includes a case where the value of the pathlossis calculated. In this manner, the expression of the pathlossappropriately includes the meaning of the value of the pathloss.

In the descriptions of the embodiment, a case of configuring variousparameters includes a case where values of the various parameters areconfigured. In this manner, the expression of various parametersappropriately includes the meaning of the value of the variousparameters.

According to the present invention, programs operated in the basestation apparatus 1 and the terminal device 2 correspond to a program ofcontrolling a CPU and the like (program of causing a computer to performfunctions), so as to realize the functions in the embodiment accordingto the present invention. Pieces of information handled in the basestation apparatus 1 and the terminal device 2 are temporarilyaccumulated in a RAM during the processing, and then, the pieces ofinformation are stored in various ROMs or various HDDs. The storedpieces of information are read by the CPU, if necessary, andmodification and writing is performed. As a recoding medium of storingthe program, any of a semiconductor medium (for example, ROM,non-volatile memory card, and the like), an optical recording medium(for example, DVD, MO, MD, CD, BD, and the like), a magnetic recordingmedium (for example, magnetic tape, flexible disc, and the like), andthe like may be used. The loaded program is executed, and thus theabove-described functions of the embodiment are performed, and anoperating system, other applications, or the like are processedtogether, based on an instruction of the program. Thus, the functionsaccording to the present invention may be realized.

In a case where distribution to markets is performed, the program may bestored in a portable recoding medium and be distributed, or may betransmitted to a server computer connected through a network such as theInternet. In this case, the present invention also includes a recordingdevice of the server computer. In the above-described embodiment, someor all of components of the base station apparatus 1 and the terminaldevice 2 may be realized as a LSI which is a typical integrated circuit.Function blocks of the base station apparatus 1 and the terminal device2 may be individually formed as a form of the chip. Some or all of thefunction blocks may be integrated so as to be formed as a form of thechip. A method of integration of circuits is not limited to the LSI, andmay be realized as a dedicated circuit or a public processor. In a casewhere the progress of the semiconductor technology causes a technologyof integration of circuits, which substitute the LSI to be expressed, anintegrated circuit obtained by using the expressed technology may beused.

Hitherto, the embodiment according to the invention is described indetail with reference to the drawings. However, the specificconfiguration is not limited to the embodiment, and includes designmodification and the like in a range without departing from the gist ofthe invention. The present invention may be changed in a scope describedin the claims, and an embodiment obtained by appropriately combiningtechnological means disclosed in different embodiments is also includedin the technological scope of the present invention. The components arecomponents described in the embodiment, and a configuration obtained bysubstituting components of exhibiting similar effects with each other isalso included.

This application invention is not limited to the above-describedembodiment. The terminal device of this application invention is notlimited to application to a mobile station, and may be applied to astationary type electronic apparatus or a non-movable electronicapparatus which is installed indoor or outdoor. Examples of such anelectronic apparatus include AV devices, kitchen utensils, cleaning orwashing devices, an air-conditioning device, business appliances,vending machines, other domestic appliances.

INDUSTRIAL APPLICABILITY

The present invention is preferably used in a radio base stationapparatus, a radio terminal device, a radio communication system, or aradio communication method.

DESCRIPTION OF REFERENCE NUMERALS

-   -   1 BASE STATION APPARATUS    -   2 TERMINAL DEVICE    -   101 HIGHER LAYER PROCESSING UNIT    -   103 CONTROL UNIT    -   105 RECEPTION UNIT    -   107 TRANSMISSION UNIT    -   109 CHANNEL MEASUREMENT UNIT    -   111 TRANSMIT/RECEIVE ANTENNA    -   1051 DECODING PORTION    -   1053 DEMODULATION PORTION    -   1055 DEMULTIPLEXING PORTION    -   1057 RADIO RECEPTION PORTION    -   1071 CODING PORTION    -   1073 MODULATION PORTION    -   1075 MULTIPLEXING PORTION    -   1077 RADIO TRANSMISSION PORTION    -   1079 DOWNLINK REFERENCE SIGNAL GENERATION PORTION    -   201 HIGHER LAYER PROCESSING UNIT    -   203 CONTROL UNIT    -   205 RECEPTION UNIT    -   207 TRANSMISSION UNIT    -   209 CHANNEL MEASUREMENT UNIT    -   211 TRANSMIT/RECEIVE ANTENNA    -   2051 DECODING PORTION    -   2053 DEMODULATION PORTION    -   2055 DEMULTIPLEXING PORTION    -   2057 RADIO RECEPTION PORTION    -   2071 CODING PORTION    -   2073 MODULATION PORTION    -   2075 MULTIPLEXING PORTION    -   2077 RADIO TRANSMISSION PORTION    -   2079 UPLINK REFERENCE SIGNAL GENERATION UNIT

The invention claimed is:
 1. A user equipment comprising: a receiverconfigured to receive a physical downlink shared channel (PDSCH) andreceive a physical downlink control channel (PDCCH) or an enhancedphysical downlink control channel (EPDCCH) with a downlink controlinformation (DCI) format for scheduling the PDSCH; and a transmitterconfigured to transmit a hybrid automatic repeat request-acknowledgement(HARQ-ACK) response for a serving cell, wherein, in a first case thatthe user equipment is configured for frequency division duplex(FDD)-time division duplex (TDD) carrier aggregation, and duplex mode ofa primary cell is TDD, the transmitter is configured to transmit, in theprimary cell, the HARQ-ACK response in uplink subframe n upon adetection of a PDSCH transmission in a secondary cell within subframen−k, where k is an element of a downlink association set, the downlinkassociation set defined on the basis of subframe n, and a downlinkassociation index (DAI) field is present in the DCI format received bythe PDSCH in subframe n−k, a value of the DAI denotes an accumulativenumber of PDCCHs or EPDCCHs with assigned PDSCH transmission and thePDCCH or the EPDCCH indicating downlink semi-persistent schedulingrelease up to subframe n−k, and in a second case that the user equipmentis configured for FDD-TDD carrier aggregation, and duplex mode of theprimary cell is FDD, the transmitter is configured to transmit, in theprimary cell, the HARQ-ACK response in uplink subframe m upon adetection of a PDSCH transmission in the secondary cell in only subframem−4, and the DAI field is not present in the DCI format received by thePDSCH in subframe m−4.
 2. The user equipment according to claim 1,wherein, in the first case and in a third case that the secondary cellis configured for FDD, an uplink/downlink configuration for the primarycell is a downlink-reference (DL-reference) uplink/downlinkconfiguration for the secondary cell.
 3. The user equipment according toclaim 2, wherein, in the first case and in a fourth case that thesecondary cell is configured for FDD and the DL-referenceuplink/downlink configuration for the primary cell is TDDuplink/downlink configuration 5, the user equipment is not expected tobe configured with more than two serving cells.